GHSA-6w86-wgwq-rgq8: Neqo qpack Neqo-qpack Has IInteger Overflow Vulnerability

MODERATE
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CWE-190
Published
Advisory Summary

GHSA-6w86-wgwq-rgq8 is a MODERATE neqo-qpack has iinteger overflow vulnerability (CWE-190: Integer Overflow or Wraparound) affecting Neqo qpack libraries in the crates.io ecosystem. The issue involves neqo-qpack has iinteger overflow in qpack dynamic table indexing. Remediation is available in the latest vendor maintenance releases.

GHSA-6w86-wgwq-rgq8 at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-6w86-wgwq-rgq8
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-190: Integer Overflow or Wraparound
Affected Product Neqo qpack
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix GHSA-6w86-wgwq-rgq8

To remediate this vulnerability, upgrade all affected Neqo qpack dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

neqo-qpack fixed: Latest secure release 
Upgrade neqo-qpack to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for neqo-qpack

How to Check if You Are Affected

To determine whether your application is affected by GHSA-6w86-wgwq-rgq8, inspect your project dependencies for Neqo qpack:

inspect dependencies for neqo-qpack

Analyze the terminal output to locate any version of Neqo qpack in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-190: Integer Overflow or Wraparound, where the product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. this occurs when an integer value is incremented to a value that is too large to store in the associated representation. when this occurs, the value may become a very small or negative number. In Neqo qpack, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary An unsanitized qpack index can lead to an integer overflow, panicing in debug mode, accessing the wrong or no dynamic table entry in release mode. What does this mean for Firefox? Firefox runs Neqo in release mode. A malicious remote can cause its own QUIC connection to fail to use qpack, i.e. compression, or enter an inconsistent state. The remote can not crash Firefox, nor affect other QUIC connections. ### Details See fuzz report in https://github.com/mozilla/neqo/issues/3406. ### PoC See test in pull request. ### Impact All Firefox users. Though vulnerability likely scoped to same connection, i.e. low impact.

GHSA-6w86-wgwq-rgq8 Affected Neqo qpack Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
neqo-qpack
 crates.io
≤ 0.22.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/mozilla/neqo/security/advisories/GHSA-6w86-wgwq-rgq8
Neqo qpack Source Repository REPOSITORY
https://github.com/mozilla/neqo/issues/3406
Neqo qpack Source Repository REPOSITORY
https://github.com/mozilla/neqo

Frequently Asked Questions

What is GHSA-6w86-wgwq-rgq8?
GHSA-6w86-wgwq-rgq8 is a security vulnerability in Neqo qpack involving neqo-qpack has iInteger overflow in qpack dynamic table indexing under CWE-190: Integer Overflow or Wraparound.
Which Neqo qpack versions are affected?
Affected versions include releases prior to current release patches across affected packages: neqo-qpack.
What version fixes GHSA-6w86-wgwq-rgq8?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is neqo-qpack affected?
Yes, neqo-qpack is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What CWE is associated with GHSA-6w86-wgwq-rgq8?
GHSA-6w86-wgwq-rgq8 is classified under CWE-190: Integer Overflow or Wraparound (The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.).
How can I check crates.io dependencies for GHSA-6w86-wgwq-rgq8?
Run the dependency tree command: 'inspect dependencies for neqo-qpack'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6w86-wgwq-rgq8",
  "modified" : "2026-03-04T20:16:26Z",
  "published" : "2026-03-04T20:16:26Z",
  "aliases" : [ ],
  "summary" : "neqo-qpack has iInteger overflow in qpack dynamic table indexing",
  "details" : "### Summary\n\nAn unsanitized qpack index can lead to an integer overflow, panicing in debug mode, accessing the wrong or no dynamic table entry in release mode.\n\nWhat does this mean for Firefox? Firefox runs Neqo in release mode. A malicious remote can cause its own QUIC connection to fail to use qpack, i.e. compression, or enter an inconsistent state. The remote can not crash Firefox, nor affect other QUIC connections. \n\n### Details\n\nSee fuzz report in https://github.com/mozilla/neqo/issues/3406.\n\n### PoC\nSee test in pull request.\n\n### Impact\nAll Firefox users. Though vulnerability likely scoped to same connection, i.e. low impact.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "neqo-qpack"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.22.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/mozilla/neqo/security/advisories/GHSA-6w86-wgwq-rgq8"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mozilla/neqo/issues/3406"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mozilla/neqo"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-190" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-04T20:16:26Z",
    "nvd_published_at" : null
  }
}