What’s Vulnerable › Vulnerabilities

CVE-2021-24029

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-15 · updated 2026-06-17
• Weakness: CWE-617

Description

A packet of death scenario is possible in mvfst via a specially crafted message during a QUIC session, which causes a crash via a failed assertion. Per QUIC specification, this particular message should be treated as a connection error. This issue affects mvfst versions prior to commit a67083ff4b8dcbb7ee2839da6338032030d712b0 and proxygen versions prior to v2021.03.15.00.

Affected products

• Facebook mvfst: before 2021-03-13 — fixed in 2021-03-13
• Facebook proxygen: before 2021.03.15.00 — fixed in 2021.03.15.00

How to fix

Upgrade to a fixed version: Facebook mvfst 2021-03-13; Facebook proxygen 2021.03.15.00. Check the vendor advisory for mitigations.

References

• https://github.com/facebookincubator/mvfst/commit/a67083ff4b8dcbb7ee2839da6338032030d712b0
• https://www.facebook.com/security/advisories/cve-2021-24029
• https://github.com/facebookincubator/mvfst/commit/a67083ff4b8dcbb7ee2839da6338032030d712b0
• https://www.facebook.com/security/advisories/cve-2021-24029

Get alerted when CVE-2021-24029 or the next vulnerability affects your stack