CVE-2026-64577 (GCVE-0-2026-64577)
Vulnerability from cvelistv5 – Published: 2026-08-05 08:09 – Updated: 2026-08-19 16:28
VLAI
EPSS
VEX
Title
gtp: check skb_pull_data() return in gtp1u_send_echo_resp()
Summary
In the Linux kernel, the following vulnerability has been resolved:
gtp: check skb_pull_data() return in gtp1u_send_echo_resp()
gtp1u_send_echo_resp() ignores skb_pull_data()'s return value. Its
caller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr +
gtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For
a 16-19 byte echo request the pull fails and returns NULL without
advancing skb->data; execution continues, and the following skb_push()
plus the IP header pushed by iptunnel_xmit() move skb->data below
skb->head, tripping skb_under_panic().
Fix it by dropping the packet when skb_pull_data() fails.
skbuff: skb_under_panic: ...
kernel BUG at net/core/skbuff.c:214!
Call Trace:
skb_push (net/core/skbuff.c:2648)
iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82)
gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920)
udp_queue_rcv_one_skb (net/ipv4/udp.c:2388)
...
Kernel panic - not syncing: Fatal exception in interrupt
Severity
7.5 (High)
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
9af41cc33471ea1efa6f77e188f055cc77d0a5c5 , < 9033fe49926f0e7421fefee922dc086417e905cf
(git)
Affected: 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 , < b3c733eaae7f362601c28ac1533d47a961cd3e1c (git) Affected: 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 , < 4fc7923871d176ce0e5fecf4a9b7bb915af790ed (git) Affected: 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 , < 961e9b1e33445f8e42859ecc020c9f60d8b69a8b (git) Affected: 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 , < cf45d748e437b8dd2dd987f27ee79c8c86f95c88 (git) Affected: 9af41cc33471ea1efa6f77e188f055cc77d0a5c5 , < cd170f051dba9ac146fabcd1b91726487c0cb9fa (git) |
guessed | |
| Linux | Linux |
Affected:
5.18
Unaffected: 0 , < 5.18 (semver) Unaffected: 6.1.183 , ≤ 6.1.* (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix) |
guessed |
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"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
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"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngtp: check skb_pull_data() return in gtp1u_send_echo_resp()\n\ngtp1u_send_echo_resp() ignores skb_pull_data()\u0027s return value. Its\ncaller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr +\ngtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For\na 16-19 byte echo request the pull fails and returns NULL without\nadvancing skb-\u003edata; execution continues, and the following skb_push()\nplus the IP header pushed by iptunnel_xmit() move skb-\u003edata below\nskb-\u003ehead, tripping skb_under_panic().\n\nFix it by dropping the packet when skb_pull_data() fails.\n\n skbuff: skb_under_panic: ...\n kernel BUG at net/core/skbuff.c:214!\n Call Trace:\n skb_push (net/core/skbuff.c:2648)\n iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82)\n gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920)\n udp_queue_rcv_one_skb (net/ipv4/udp.c:2388)\n ...\n Kernel panic - not syncing: Fatal exception in interrupt"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - A crafted GTP-U Echo Request to UDP port 2152 reaches gtp_encap_recv \u2192 gtp1u_udp_encap_recv \u2192 gtp1u_send_echo_resp via the in-kernel UDP encap receive path, so a remote IP peer can trigger the bug without local access.\nAC:L - The attacker fully controls the packet: a 16\u201319 byte GTP-U Echo Request with the S flag set and TEID 0 reliably fails the unchecked 20-byte pull and drives the subsequent skb_push path into skb_under_panic with no race or external condition required.\nPR:N - GTP-U echo handling runs on unauthenticated received UDP datagrams once a GTP device with kernel-created sockets exists; the attacker needs no credentials or local privileges on the target.\nUI:N - No victim action is required; packet delivery to the GTP-U encap socket alone invokes the vulnerable echo-response path.\nS:U - Impact is a kernel BUG/panic in the host GTP/network stack within the same security authority; it does not cross a VM, IOMMU, or other separate boundary.\nC:N - The failure is a deterministic skb headroom underflow caught by skb_under_panic/BUG with no out-of-bounds read, UAF, or other information-disclosure primitive identified.\nI:N - skb_push detects data \u003c head and BUG()s before further attacker-controlled writes; this is an availability crash, not an exploitable write or control-flow hijack primitive.\nA:H - The commit-reproduced path hits skb_under_panic and a fatal kernel BUG in interrupt context, causing kernel panic and full denial of service that can be retriggered by further crafted echo requests."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:28:59.684Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/9033fe49926f0e7421fefee922dc086417e905cf"
},
{
"url": "https://git.kernel.org/stable/c/b3c733eaae7f362601c28ac1533d47a961cd3e1c"
},
{
"url": "https://git.kernel.org/stable/c/4fc7923871d176ce0e5fecf4a9b7bb915af790ed"
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{
"url": "https://git.kernel.org/stable/c/cd170f051dba9ac146fabcd1b91726487c0cb9fa"
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"title": "gtp: check skb_pull_data() return in gtp1u_send_echo_resp()",
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"cveId": "CVE-2026-64577",
"datePublished": "2026-08-05T08:09:33.135Z",
"dateReserved": "2026-07-19T15:36:31.798Z",
"dateUpdated": "2026-08-19T16:28:59.684Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-64577",
"date": "2026-11-09",
"epss": "0.00576",
"percentile": "0.47771"
},
"microsoft_vex": {
"current_release_date": "2026-08-09T01:43:14.000Z",
"cve": "CVE-2026-64577",
"id": "msrc_CVE-2026-64577",
"initial_release_date": "2026-08-09T01:43:14.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "gtp: check skb_pull_data() return in gtp1u_send_echo_resp()",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-64577.json",
"version": "1"
},
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"version": "0",
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}
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"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngtp: check skb_pull_data() return in gtp1u_send_echo_resp()\n\ngtp1u_send_echo_resp() ignores skb_pull_data()\u0027s return value. Its\ncaller gtp1u_udp_encap_recv() only guarantees 16 bytes (udphdr +\ngtp1_header), but the pull requests 20 (gtp1_header_long + udphdr). For\na 16-19 byte echo request the pull fails and returns NULL without\nadvancing skb-\u003edata; execution continues, and the following skb_push()\nplus the IP header pushed by iptunnel_xmit() move skb-\u003edata below\nskb-\u003ehead, tripping skb_under_panic().\n\nFix it by dropping the packet when skb_pull_data() fails.\n\n skbuff: skb_under_panic: ...\n kernel BUG at net/core/skbuff.c:214!\n Call Trace:\n skb_push (net/core/skbuff.c:2648)\n iptunnel_xmit (net/ipv4/ip_tunnel_core.c:82)\n gtp_encap_recv (drivers/net/gtp.c:701 drivers/net/gtp.c:808 drivers/net/gtp.c:920)\n udp_queue_rcv_one_skb (net/ipv4/udp.c:2388)\n ...\n Kernel panic - not syncing: Fatal exception in interrupt"
}
],
"id": "CVE-2026-64577",
"lastModified": "2026-08-19T17:20:17.690",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
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"impactScore": 3.6,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-05T08:16:37.630",
"references": [
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"url": "https://git.kernel.org/stable/c/4fc7923871d176ce0e5fecf4a9b7bb915af790ed"
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}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-11-05T22:07:40+00:00",
"cve": "CVE-2026-64577",
"id": "CVE-2026-64577",
"initial_release_date": "2026-08-05T00:00:00+00:00",
"product_status:known_not_affected": "200",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: gtp: check skb_pull_data() return in gtp1u_send_echo_resp()",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64577.json",
"version": "3"
}
}
}
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