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CVE-2026-63495 (GCVE-0-2026-63495)

Vulnerability from nvd – Published: 2026-08-20 17:49 – Updated: 2026-08-20 19:17

Title

Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames

Summary

Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a total message-size limit. An unauthenticated remote client can repeatedly send fragmented WebSocket frames below WS_MAX_RECV_FRAME_SZ with FIN=0, causing the evbuffer to grow without bound until the process or host exhausts memory. This issue is fixed in version 2.2.2-alpha.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 19:16 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/291c4…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha-dev, < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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      "title": "Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames"
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CVE-2026-63388 (GCVE-0-2026-63388)

Vulnerability from nvd – Published: 2026-08-20 17:44 – Updated: 2026-08-21 21:46

Title

Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.4 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 21:00 UTC

CWE

CWE-617 - Reachable Assertion
CWE-787 - Out-of-bounds Write

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/52057…	x_refsource_MISC
https://github.com/libevent/libevent/commit/ef38f…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: < 2.1.13 Affected: >= 2.2.0-alpha, < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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CVE-2026-63387 (GCVE-0-2026-63387)

Vulnerability from nvd – Published: 2026-08-20 17:53 – Updated: 2026-08-25 15:12

Title

Libevent: Off-by-one stack buffer overflow in dnsname_to_labels via crafted DNS server response

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_request_format_response. The final-label check permits j plus label_len plus one to equal buf_len, after which the terminating null byte is written to buf[buf_len]. A crafted DNS server response containing PTR, CNAME, MX, NS, or SOA data can trigger the one-byte out-of-bounds write and crash or corrupt the process. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

7 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 15:11 UTC

CWE

CWE-121 - Stack-based Buffer Overflow
CWE-193 - Off-by-one Error
CWE-787 - Out-of-bounds Write

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63385 (GCVE-0-2026-63385)

Vulnerability from nvd – Published: 2026-08-20 17:55 – Updated: 2026-08-21 21:46

Title

Libevent: HTTP header handling bugs create risk of access control bypass.

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 20:58 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/758be…	x_refsource_MISC
https://github.com/libevent/libevent/commit/9170d…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63384 (GCVE-0-2026-63384)

Vulnerability from nvd – Published: 2026-08-20 17:53 – Updated: 2026-08-20 19:50

Title

Libevent: `evtag_unmarshal_header()` decodes a wire `uint32` length into a signed `int` return value.

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an incorrect integer conversion in event_tagging.c when evtag_unmarshal_header uses evtag_decode_int to decode an attacker-controlled uint32 payload length and returns it as a signed int. Values above INT_MAX become negative or truncated, and evtag_unmarshal_string can use the converted value in allocation sizing, producing a wrapped large allocation request and denial of service. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 19:50 UTC

CWE

CWE-190 - Integer Overflow or Wraparound

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/109c1…	x_refsource_MISC
https://github.com/libevent/libevent/commit/5e3c6…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63383 (GCVE-0-2026-63383)

Vulnerability from nvd – Published: 2026-08-20 17:48 – Updated: 2026-08-20 18:41

Title

Libevent: decode_tag_internal() can lead to out-of-bounds read

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 18:37 UTC

CWE

CWE-125 - Out-of-bounds Read

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/91ed8…	x_refsource_MISC
https://github.com/libevent/libevent/commit/e1f9e…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63382 (GCVE-0-2026-63382)

Vulnerability from nvd – Published: 2026-08-20 17:51 – Updated: 2026-08-20 19:33

Title

libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 19:33 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

7 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/10abb…	x_refsource_MISC
https://github.com/libevent/libevent/commit/5119c…	x_refsource_MISC
https://github.com/libevent/libevent/commit/83ba6…	x_refsource_MISC
https://github.com/libevent/libevent/commit/ac387…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63381 (GCVE-0-2026-63381)

Vulnerability from nvd – Published: 2026-08-20 17:50 – Updated: 2026-08-21 21:46

Title

Libevent: Dangling Pointer in `evbuffer_add_buffer_reference`

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

5.8 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 20:58 UTC

CWE

CWE-908 - Use of Uninitialized Resource

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/5cb95…	x_refsource_MISC
https://github.com/libevent/libevent/commit/9db09…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63380 (GCVE-0-2026-63380)

Vulnerability from nvd – Published: 2026-08-20 17:52 – Updated: 2026-08-25 15:11

Title

Libevent: Null Pointer Dereference in `evws_new_session`

Summary

Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evws_new_session enters its error path after evhttp_start_ws_ succeeds but bufferevent_enable_locking_ fails. evws_connection_free sees a non-null http_server and unconditionally calls TAILQ_REMOVE even though the session was never inserted into http_server->ws_sessions. A local caller able to induce this allocation or locking failure can crash the process. This issue is fixed in version 2.2.2-alpha.

Severity

5.7 (Medium)


                        
                          CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 15:10 UTC

CWE

CWE-416 - Use After Free
CWE-476 - NULL Pointer Dereference

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/825c1…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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CVE-2026-63379 (GCVE-0-2026-63379)

Vulnerability from nvd – Published: 2026-08-20 17:55 – Updated: 2026-08-25 15:14

Title

Libevent: HTTP Header smuggling

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 15:14 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/87e8e…	x_refsource_MISC
https://github.com/libevent/libevent/commit/b8470…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: < 2.1.13 Affected: >= 2.2.0-alpha, < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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CVE-2026-63385 (GCVE-0-2026-63385)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:55 – Updated: 2026-08-21 21:46

Title

Libevent: HTTP header handling bugs create risk of access control bypass.

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 20:58 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/758be…	x_refsource_MISC
https://github.com/libevent/libevent/commit/9170d…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63379 (GCVE-0-2026-63379)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:55 – Updated: 2026-08-25 15:14

Title

Libevent: HTTP Header smuggling

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 15:14 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/87e8e…	x_refsource_MISC
https://github.com/libevent/libevent/commit/b8470…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: < 2.1.13 Affected: >= 2.2.0-alpha, < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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CVE-2026-63387 (GCVE-0-2026-63387)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:53 – Updated: 2026-08-25 15:12

Title

Libevent: Off-by-one stack buffer overflow in dnsname_to_labels via crafted DNS server response

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_request_format_response. The final-label check permits j plus label_len plus one to equal buf_len, after which the terminating null byte is written to buf[buf_len]. A crafted DNS server response containing PTR, CNAME, MX, NS, or SOA data can trigger the one-byte out-of-bounds write and crash or corrupt the process. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

7 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 15:11 UTC

CWE

CWE-121 - Stack-based Buffer Overflow
CWE-193 - Off-by-one Error
CWE-787 - Out-of-bounds Write

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63384 (GCVE-0-2026-63384)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:53 – Updated: 2026-08-20 19:50

Title

Libevent: `evtag_unmarshal_header()` decodes a wire `uint32` length into a signed `int` return value.

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an incorrect integer conversion in event_tagging.c when evtag_unmarshal_header uses evtag_decode_int to decode an attacker-controlled uint32 payload length and returns it as a signed int. Values above INT_MAX become negative or truncated, and evtag_unmarshal_string can use the converted value in allocation sizing, producing a wrapped large allocation request and denial of service. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 19:50 UTC

CWE

CWE-190 - Integer Overflow or Wraparound

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/109c1…	x_refsource_MISC
https://github.com/libevent/libevent/commit/5e3c6…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63380 (GCVE-0-2026-63380)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:52 – Updated: 2026-08-25 15:11

Title

Libevent: Null Pointer Dereference in `evws_new_session`

Summary

Libevent is an event notification library. Prior to 2.2.2-alpha, libevent can dereference invalid list pointers in ws.c when evws_new_session enters its error path after evhttp_start_ws_ succeeds but bufferevent_enable_locking_ fails. evws_connection_free sees a non-null http_server and unconditionally calls TAILQ_REMOVE even though the session was never inserted into http_server->ws_sessions. A local caller able to induce this allocation or locking failure can crash the process. This issue is fixed in version 2.2.2-alpha.

Severity

5.7 (Medium)


                        
                          CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-25 15:10 UTC

CWE

CWE-416 - Use After Free
CWE-476 - NULL Pointer Dereference

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/825c1…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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CVE-2026-63382 (GCVE-0-2026-63382)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:51 – Updated: 2026-08-20 19:33

Title

libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 19:33 UTC

CWE

CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

Assigner

GitHub_M mitre root

References

7 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/10abb…	x_refsource_MISC
https://github.com/libevent/libevent/commit/5119c…	x_refsource_MISC
https://github.com/libevent/libevent/commit/83ba6…	x_refsource_MISC
https://github.com/libevent/libevent/commit/ac387…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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      "title": "libevent evhttp: Multiple HTTP Parser Bugs Enable Request Smuggling"
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}

CVE-2026-63381 (GCVE-0-2026-63381)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:50 – Updated: 2026-08-21 21:46

Title

Libevent: Dangling Pointer in `evbuffer_add_buffer_reference`

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a use-after-free in buffer.c when evbuffer_add_buffer_reference processes an output buffer whose out_total_len is zero. evbuffer_free_all_chains frees the initial empty chain without resetting outbuf->first, outbuf->last, or outbuf->last_with_datap, and APPEND_CHAIN_MULTICAST subsequently dereferences the dangling chain pointer. A caller that can drive this buffer state can cause memory corruption or a process crash. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

5.8 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 20:58 UTC

CWE

CWE-908 - Use of Uninitialized Resource

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/5cb95…	x_refsource_MISC
https://github.com/libevent/libevent/commit/9db09…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

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CVE-2026-63495 (GCVE-0-2026-63495)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:49 – Updated: 2026-08-20 19:17

Title

Libevent: Unbounded memory accumulation in WebSocket server via fragmented frames

Summary

Libevent is an event notification library. From 2.2.0-alpha-dev until 2.2.2-alpha, the libevent WebSocket server in ws.c accumulates fragmented frames in evws->incomplete_frames without enforcing a total message-size limit. An unauthenticated remote client can repeatedly send fragmented WebSocket frames below WS_MAX_RECV_FRAME_SZ with FIN=0, causing the evbuffer to grow without bound until the process or host exhausts memory. This issue is fixed in version 2.2.2-alpha.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 19:16 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/291c4…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha-dev, < 2.2.2-alpha

Show details on NVD website

JSON

To clipboard

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CVE-2026-63383 (GCVE-0-2026-63383)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:48 – Updated: 2026-08-20 18:41

Title

Libevent: decode_tag_internal() can lead to out-of-bounds read

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-20 18:37 UTC

CWE

CWE-125 - Out-of-bounds Read

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/91ed8…	x_refsource_MISC
https://github.com/libevent/libevent/commit/e1f9e…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: >= 2.2.0-alpha, < 2.2.2-alpha Affected: < 2.1.13

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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                "id": "CVE-2026-63383",
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CVE-2026-63388 (GCVE-0-2026-63388)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:44 – Updated: 2026-08-21 21:46

Title

Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.4 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 21:00 UTC

CWE

CWE-617 - Reachable Assertion
CWE-787 - Out-of-bounds Write

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/52057…	x_refsource_MISC
https://github.com/libevent/libevent/commit/ef38f…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
libevent	libevent	Affected: < 2.1.13 Affected: >= 2.2.0-alpha, < 2.2.2-alpha

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-63388",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-21T21:00:24.903079Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-21T21:46:40.675Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "libevent",
          "vendor": "libevent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.1.13"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.2.0-alpha, \u003c 2.2.2-alpha"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-617",
              "description": "CWE-617: Reachable Assertion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787: Out-of-bounds Write",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-20T17:44:18.435Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338"
        },
        {
          "name": "https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9"
        },
        {
          "name": "https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72"
        },
        {
          "name": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"
        },
        {
          "name": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"
        }
      ],
      "source": {
        "advisory": "GHSA-cvq5-vrvr-j338",
        "discovery": "UNKNOWN"
      },
      "title": "Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-63388",
    "datePublished": "2026-08-20T17:44:18.435Z",
    "dateReserved": "2026-07-16T17:39:30.171Z",
    "dateUpdated": "2026-08-21T21:46:40.675Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Find a vulnerability

Search criteria

20 vulnerabilities by libevent

CVE-2026-63495 (GCVE-0-2026-63495)

CVE-2026-63388 (GCVE-0-2026-63388)

CVE-2026-63387 (GCVE-0-2026-63387)

CVE-2026-63385 (GCVE-0-2026-63385)

CVE-2026-63384 (GCVE-0-2026-63384)

CVE-2026-63383 (GCVE-0-2026-63383)

CVE-2026-63382 (GCVE-0-2026-63382)

CVE-2026-63381 (GCVE-0-2026-63381)

CVE-2026-63380 (GCVE-0-2026-63380)

CVE-2026-63379 (GCVE-0-2026-63379)

CVE-2026-63385 (GCVE-0-2026-63385)

CVE-2026-63379 (GCVE-0-2026-63379)

CVE-2026-63387 (GCVE-0-2026-63387)

CVE-2026-63384 (GCVE-0-2026-63384)

CVE-2026-63380 (GCVE-0-2026-63380)

CVE-2026-63382 (GCVE-0-2026-63382)

CVE-2026-63381 (GCVE-0-2026-63381)

CVE-2026-63495 (GCVE-0-2026-63495)

CVE-2026-63383 (GCVE-0-2026-63383)

CVE-2026-63388 (GCVE-0-2026-63388)