CVE-2025-61684: Quicly has assertion failures

Published Jan 19, 2026
·
Updated

Quicly, an IETF QUIC protocol implementation, is susceptible to a denial-of-service attack prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e. A remote attacker can exploit these bugs to trigger an assertion failure that crashes process using Quicly. Commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e fixes the issue.

Affected Software

2 affected components
Quicly<d9d3df6a8530a102b57d840e39b0311ce5c9e14e
h2o Quicly<2026-01-18

Event History

Jan 19, 2026
CVE Published
via MITRE·03:18 PM
Data Sourced
via MITRE·03:18 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·04:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2025-61684?

CVE-2025-61684 is classified as a denial-of-service vulnerability due to assertion failures in Quicly.

2

How do I fix CVE-2025-61684?

To fix CVE-2025-61684, update Quicly to version after commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e.

3

Which versions of Quicly are affected by CVE-2025-61684?

CVE-2025-61684 affects all versions of Quicly prior to commit d9d3df6a8530a102b57d840e39b0311ce5c9e14e.

4

What type of attack does CVE-2025-61684 enable?

CVE-2025-61684 enables a remote denial-of-service attack that can crash the process using Quicly.

5

Is CVE-2025-61684 a code execution vulnerability?

No, CVE-2025-61684 is not a code execution vulnerability but rather a denial-of-service issue.

Contact

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