CVE-2026-119236
mvfst CRYPTO Frame Memory Exhaustion Denial of Service
Description
An mvfst QUIC server retained CRYPTO frame data received at an encryption level (Initial or Handshake) that the TLS handshake had already moved past. Because the transport treated this data as delivered, it did not count against the CRYPTO stream buffer limit. A remote, unauthenticated client could complete a handshake, withhold its acknowledgment of the server's HANDSHAKE_DONE frame so that Handshake keys stay in use, and keep sending Handshake-level CRYPTO data at increasing offsets, causing unbounded memory growth on the server and leading to denial of service. This issue affects mvfst versions prior to v2026.11.09.00.
INFO
Published Date :
Nov. 11, 2026, 5:17 p.m.
Last Modified :
Nov. 11, 2026, 5:17 p.m.
Remotely Exploit :
No
Source :
[email protected]
Solution
- Update mvfst to version v2026.11.09.00 or later.
- Verify handshake acknowledgment handling.
- Monitor server memory usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-119236.
| URL | Resource |
|---|---|
| https://github.com/meta/mvfst/commit/7e5cff58e8cbed87793141ceeca0a8a343c67c44 | |
| https://www.facebook.com/security/advisories/cve-2026-119236 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-119236 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-119236
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-119236 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-119236 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Nov. 11, 2026
Action Type Old Value New Value Added Description An mvfst QUIC server retained CRYPTO frame data received at an encryption level (Initial or Handshake) that the TLS handshake had already moved past. Because the transport treated this data as delivered, it did not count against the CRYPTO stream buffer limit. A remote, unauthenticated client could complete a handshake, withhold its acknowledgment of the server's HANDSHAKE_DONE frame so that Handshake keys stay in use, and keep sending Handshake-level CRYPTO data at increasing offsets, causing unbounded memory growth on the server and leading to denial of service. This issue affects mvfst versions prior to v2026.11.09.00. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/119xxx/CVE-2026-119236.json">CVE-2026-119236</a> Added Reference https://github.com/meta/mvfst/commit/7e5cff58e8cbed87793141ceeca0a8a343c67c44 Added Reference https://www.facebook.com/security/advisories/cve-2026-119236