CVE-2026-63384
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an incorrect integer conversion in event_tagging.c when evtag_unmarshal_header uses evtag_decode_int to decode an attacker-controlled uint32 payload length and returns it as a signed int. Values above INT_MAX become negative or truncated, and evtag_unmarshal_string can use the converted value in allocation sizing, producing a wrapped large allocation request and denial of service. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
What this means for your business
- FIRST's prediction model gives it a 0.5% chance of attack attempts being seen in the next 30 days, ranking above 41% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
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Scoring
- CVSS
- Not yet scored
- CVSS v4
- 8.7
- Weakness
- CWE-190
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-08-20
- Last modified
- 2026-09-09
- Sources
- NVD
References
- https://github.com/libevent/libevent/commit/109c16499282959d70f56ec3baf4c8b1e6646bda
- https://github.com/libevent/libevent/commit/5e3c6ebe342b34c5a9bcf48e9a32ad6708b9c416
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
- https://github.com/libevent/libevent/security/advisories/GHSA-45c6-qx49-89m8
- https://github.com/libevent/libevent/security/advisories/GHSA-45c6-qx49-89m8