Vulnerability-Lookup

GHSA-VVGJ-X9JQ-8CJ9

Vulnerability from github – Published: 2026-06-03 20:59 – Updated: 2026-06-03 20:59

Summary

quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion

Details

Summary

An attacker can cause excessive memory allocation in quic-go's HTTP/3 client and server implementations by sending a QPACK-encoded HEADERS frame that decodes into a large trailer field section with many unique field names and/or large values. The implementation builds an http.Header for the corresponding http.Request or http.Response, while only enforcing limits on the size of the QPACK-compressed HEADERS frame, not on the decoded field section. This can lead to memory exhaustion.

This is very similar to CVE-2025-64702. The difference is that this issue uses HTTP trailers, rather than HTTP headers, as the attack vector.

Impact

A misbehaving or malicious peer can cause a denial-of-service (DoS) attack against quic-go's HTTP/3 servers or clients by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion. This affects both servers and clients due to symmetric header construction.

Details

In HTTP/3, field sections are compressed using QPACK (RFC 9204). Field sections are used for both HTTP headers and trailers. quic-go's HTTP/3 server and client decode the QPACK-encoded HEADERS frame into header fields, then construct an http.Request or http.Response.

http3.Server.MaxHeaderBytes and http3.Transport.MaxResponseHeaderBytes limit the encoded HEADERS frame size, with defaults of 1 MB for servers and 10 MB for clients. However, they did not limit the decoded field section size. A maliciously crafted HEADERS frame carrying trailers can expand to about 50x the encoded size using QPACK static table entries with long names and/or values.

RFC 9114 requires endpoints to enforce decoded field section size limits via SETTINGS, which quic-go did not do for trailers.

The Fix

quic-go now enforces RFC 9114 decoded field section size limits for trailers as well. It incrementally decodes QPACK entries and checks the field section size after each entry, aborting the stream if an entry causes the limit to be exceeded.

Severity

5.3 (Medium)


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

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.59.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/quic-go/quic-go"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.59.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40898"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-03T20:59:49Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nAn attacker can cause excessive memory allocation in quic-go\u0027s HTTP/3 client and server implementations by sending a QPACK-encoded HEADERS frame that decodes into a large trailer field section with many unique field names and/or large values. The implementation builds an `http.Header` for the corresponding `http.Request` or `http.Response`, while only enforcing limits on the size of the QPACK-compressed HEADERS frame, not on the decoded field section. This can lead to memory exhaustion.\n\nThis is very similar to CVE-2025-64702. The difference is that this issue uses HTTP trailers, rather than HTTP headers, as the attack vector.\n\n## Impact\n\nA misbehaving or malicious peer can cause a denial-of-service (DoS) attack against quic-go\u0027s HTTP/3 servers or clients by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion. This affects both servers and clients due to symmetric header construction.\n\n## Details\n\nIn HTTP/3, field sections are compressed using QPACK (RFC 9204). Field sections are used for both HTTP headers and trailers. quic-go\u0027s HTTP/3 server and client decode the QPACK-encoded HEADERS frame into header fields, then construct an `http.Request` or `http.Response`.\n\n`http3.Server.MaxHeaderBytes` and `http3.Transport.MaxResponseHeaderBytes` limit the encoded HEADERS frame size, with defaults of 1 MB for servers and 10 MB for clients. However, they did not limit the decoded field section size. A maliciously crafted HEADERS frame carrying trailers can expand to about 50x the encoded size using QPACK static table entries with long names and/or values.\n\nRFC 9114 requires endpoints to enforce decoded field section size limits via SETTINGS, which quic-go did not do for trailers.\n\n## The Fix\n\nquic-go now enforces RFC 9114 decoded field section size limits for trailers as well. It incrementally decodes QPACK entries and checks the field section size after each entry, aborting the stream if an entry causes the limit to be exceeded.",
  "id": "GHSA-vvgj-x9jq-8cj9",
  "modified": "2026-06-03T20:59:49Z",
  "published": "2026-06-03T20:59:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/quic-go/quic-go/security/advisories/GHSA-vvgj-x9jq-8cj9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/quic-go/quic-go/pull/5642"
    },
    {
      "type": "WEB",
      "url": "https://github.com/quic-go/quic-go/commit/c56e8c79d1627cc1ed6005b421b4b0adadd83665"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-g754-hx8w-x2g6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/quic-go/quic-go"
    },
    {
      "type": "WEB",
      "url": "https://github.com/quic-go/quic-go/releases/tag/v0.59.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion "
}

CVE-2026-40898 (GCVE-0-2026-40898)

Vulnerability from cvelistv5 – Published: 2026-06-04 17:43 – Updated: 2026-06-04 18:40

Title

quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion

Summary

quic-go is an implementation of the QUIC protocol in Go. Prior to version 0.59.1, an attacker can cause excessive memory allocation in quic-go's HTTP/3 client and server implementations by sending a QPACK-encoded HEADERS frame that decodes into a large trailer field section with many unique field names and/or large values. The implementation builds an `http.Header` for the corresponding `http.Request` or `http.Response`, while only enforcing limits on the size of the QPACK-compressed HEADERS frame, not on the decoded field section. This can lead to memory exhaustion. This is very similar to CVE-2025-64702. The difference is that this issue uses HTTP trailers, rather than HTTP headers, as the attack vector. A misbehaving or malicious peer can cause a denial-of-service (DoS) attack against quic-go's HTTP/3 servers or clients by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion. This affects both servers and clients due to symmetric header construction. Version 0.59.1 enforces RFC 9114 decoded field section size limits for trailers as well. It incrementally decodes QPACK entries and checks the field section size after each entry, aborting the stream if an entry causes the limit to be exceeded.

Severity

5.3 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M

References

2 references

URL	Tags
https://github.com/quic-go/quic-go/security/advis…	x_refsource_CONFIRM
https://github.com/quic-go/quic-go/releases/tag/v0.59.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
quic-go	quic-go	Affected: < 0.59.1

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-40898",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-04T18:40:25.619349Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
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        "providerMetadata": {
          "dateUpdated": "2026-06-04T18:40:44.304Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "quic-go",
          "vendor": "quic-go",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.59.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "quic-go is an implementation of the QUIC protocol in Go. Prior to version 0.59.1, an attacker can cause excessive memory allocation in quic-go\u0027s HTTP/3 client and server implementations by sending a QPACK-encoded HEADERS frame that decodes into a large trailer field section with many unique field names and/or large values. The implementation builds an `http.Header` for the corresponding `http.Request` or `http.Response`, while only enforcing limits on the size of the QPACK-compressed HEADERS frame, not on the decoded field section. This can lead to memory exhaustion. This is very similar to CVE-2025-64702. The difference is that this issue uses HTTP trailers, rather than HTTP headers, as the attack vector. A misbehaving or malicious peer can cause a denial-of-service (DoS) attack against quic-go\u0027s HTTP/3 servers or clients by triggering excessive memory allocation, potentially leading to crashes or resource exhaustion. This affects both servers and clients due to symmetric header construction. Version 0.59.1 enforces RFC 9114 decoded field section size limits for trailers as well. It incrementally decodes QPACK entries and checks the field section size after each entry, aborting the stream if an entry causes the limit to be exceeded."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "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:L",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
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              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-04T17:43:36.803Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/quic-go/quic-go/security/advisories/GHSA-vvgj-x9jq-8cj9",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/quic-go/quic-go/security/advisories/GHSA-vvgj-x9jq-8cj9"
        },
        {
          "name": "https://github.com/quic-go/quic-go/releases/tag/v0.59.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/quic-go/quic-go/releases/tag/v0.59.1"
        }
      ],
      "source": {
        "advisory": "GHSA-vvgj-x9jq-8cj9",
        "discovery": "UNKNOWN"
      },
      "title": "quic-go: HTTP/3 QPACK Trailer Expansion Memory Exhaustion"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-40898",
    "datePublished": "2026-06-04T17:43:36.803Z",
    "dateReserved": "2026-04-15T16:37:22.766Z",
    "dateUpdated": "2026-06-04T18:40:44.304Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-VVGJ-X9JQ-8CJ9

Summary

Impact

Details

The Fix

CVE-2026-40898 (GCVE-0-2026-40898)

Tags

Sightings

Nomenclature