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GHSA-6w86-wgwq-rgq8

MediumCVSS 5.1 / 10
Published Mar 4, 2026·Last modified Mar 4, 2026
Affected Components(0)

No affected components available

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.

Risk Scores
Base Score
5.1

The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
1.2

Limited exploitation activity has been observed. Close monitoring and planned remediation are recommended.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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