PT-2026-25516 · Crates.Io · Neqo-Qpack

Published 2026-03-04 · Updated 2026-03-04

OSV

CVSS v4.0

5.1

Medium

Base vector

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

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.

Fix

Integer Overflow

Weakness Enumeration

CWE-190

Related Identifiers

GHSA-6W86-WGWQ-RGQ8

Affected Products

Neqo-Qpack

References · 4

• https://osv.dev/vulnerability/GHSA-6w86-wgwq-rgq8 · Vendor Advisory
• https://github.com/mozilla/neqo/security/advisories/GHSA-6w86-wgwq-rgq8 · Note
• https://github.com/mozilla/neqo · Note
• https://github.com/mozilla/neqo/issues/3406 · Note