Quick answers
- Is CVE-2026-119234 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-119234 being exploited in the wild.
- How severe is CVE-2026-119234?
- Informational severity, published 11 November 2026.
- Which products and versions are affected?
- Meta Mvfst prior to v2026.11.09.0.
- Is there a fix for CVE-2026-119234?
- Yes: fixed in v2026.11.09.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-119234 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-119234?
- Check whether you run Meta Mvfst 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.
How to fix
- Fixed in: v2026.11.09.0
Technical details
mvfst's STREAM frame handling fails to properly merge or compact out-of-order fragments, allowing a small received fragment to keep a much larger receive buffer alive. A remote unauthenticated attacker can send many small, non-contiguous stream fragments to exceed advertised flow control limits and trigger denial of service through memory exhaustion and CPU consumption during reassembly. The vulnerability is fixed in mvfst v2026.11.09.0 and later.
Affected products
- Meta mvfst prior to v2026.11.09.0
Timeline
- 2026-11-11: disclosed