Vulnerability · Published Sep 28, 2026 · Assigned by Meta
CVE-2026-91096
High 7.5
In plain English
A high-severity use-after-free in proxygen from Facebook. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.3%top 82.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
In proxygen from v2024.10.28.00 until v2026.09.28.00, WebTransportImpl::terminateSessionStreams (WebTransportImpl::destroy in releases before v2025.08.18.00) failed to unregister read callbacks for streams that were no longer open before destroying them. The transport could then invoke a read callback that had been freed.
Affected products (as reported)
Weakness: CWE-416 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
- https://www.facebook.com/security/advisories/cve-2026-91096 x_refsource_CONFIRM
- https://github.com/facebook/proxygen/commit/479eb5574195764e80e6cedebef669f6baa85083 x_refsource_MISC