Quick answers
- Is CVE-2026-91096 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-91096 being exploited in the wild.
- How severe is CVE-2026-91096?
- Informational severity, published 28 September 2026.
- Which products and versions are affected?
- Meta Proxygen v2024.10.28.00 through before v2026.09.28.00.
- Is there a fix for CVE-2026-91096?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-91096 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-91096?
- Check whether you run Meta Proxygen at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A use-after-free vulnerability exists in WebTransportImpl::terminateSessionStreams (or WebTransportImpl::destroy in older releases) where read callbacks are not unregistered from closed streams before the transport is destroyed. The vulnerability allows invocation of freed callback pointers during transport shutdown, leading to potential code execution or denial of service. The defect affects versions from v2024.10.28.00 through v2026.09.28.00 and was patched in the specified version.
Affected products
- Meta proxygen v2024.10.28.00 through before v2026.09.28.00