CVE-2026-119236: Facebook mvfst · Unthrottled Resource Allocation
Affects Facebook mvfstSource CVE Database V5
Not known to be exploited : upgrade to v2026.11.09.00 soon.
Data as of 11 Nov 2026, 17:31 UTC
Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD
Thin evidence
One scorer or none- Patch
- Available – fixed in v2026.11.09.00
Exploitation evidence
Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 11 Nov 2026.
What to do
Upgrade Facebook mvfst to v2026.11.09.00.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Facebookmvfst | Affected
| Fixed in
|
AI-suggested
This vulnerability is fixed in mvfst version v2026.11.09.00. Users should upgrade to this version or later to remediate the issue.
Description
A vulnerability in Facebook's mvfst QUIC server allows a remote unauthenticated client to cause unbounded memory growth by sending Handshake-level CRYPTO data after the TLS handshake has progressed, leading to denial of service. This affects mvfst versions prior to v2026.11.09.00. The issue arises because the server retains CRYPTO frame data at encryption levels already passed by the handshake and does not count this data against buffer limits.