CVE-2026-119236

Published Nov 11, 2026 CVSS n/a EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Title Unbounded Memory Growth in mvfst QUIC Server from Excessive Handshake‑Level CRYPTO Data
Weaknesses CWE-399
Type Values Removed Values Added
First Time appeared Facebook
Facebook mvfst
Vendors & Products Facebook
Facebook mvfst
Type Values Removed Values Added
Title Unbounded Memory Growth in mvfst QUIC Server from Excessive Handshake‑Level CRYPTO Data
Weaknesses CWE-399
Type Values Removed Values 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.
References
Weaknesses

No weakness.

Sources

Status
PUBLISHED
Assigner
Meta
Published
Updated
Nov 11, 2026, 4:55 PM
Reserved
Oct 29, 2026, 5:01 PM
Status
Awaiting Analysis
Published
Nov 11, 2026, 5:17 PM
Modified
Nov 12, 2026, 8:04 PM