GHSA-6w86-wgwq-rgq8
neqo-qpack has iInteger overflow in qpack dynamic table indexing
GHSA-6w86-wgwq-rgq8 is a medium vulnerability (CVSS 5.1) in neqo-qpack, published March 4, 2026. No source lists public exploit code. No source names a fixed version.
- Severity
- 5.1 MediumCVSS 4.0, GitHub Advisories
- Exploit chance
- UnscoredNo EPSS score yet
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
- No fix listedNo source names one
Description
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Affected packages
| Package | Affected | Fixed |
|---|---|---|
neqo-qpackcrates.io | through 0.22.2 | None known |
What each source reports
GitHub Advisories Score used
neqo-qpack has iInteger overflow in qpack dynamic table indexing
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.
- Record
GHSA-6w86-wgwq-rgq8- CVSS 4.0
- 5.1 Medium
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 - Weakness
- CWE-190
- Updated
- 2026-11-02
OSV
neqo-qpack has iInteger overflow in qpack dynamic table indexing
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.
- Record
GHSA-6w86-wgwq-rgq8- CVSS 4.0
- 5.1 Medium
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 - Weakness
- CWE-190
- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.