CVE-2021-29626 Use after free in FreeBSD

Medium 5.5 Published 7 Apr 2021 Updated 3 Aug 2024

An unprivileged process can read private data from other processes or the kernel due to a use-after-free flaw in copy-on-write logic.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2021-29626?

CVE-2021-29626 is a medium-severity use after free vulnerability in Freebsd Freebsd, published on 7 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In FreeBSD 13.0-STABLE before n245117, 12.2-STABLE before r369551, 11.4-STABLE before r369559, 13.0-RC5 before p1, 12.2-RELEASE before p6, and 11.4-RELEASE before p9, copy-on-write logic failed to invalidate shared memory page mappings between multiple processes allowing an unprivileged process to maintain a mapping after it is freed, allowing the process to read private data belonging to other processes or the kernel.

Weakness: CWE-416

Which versions are affected by CVE-2021-29626?

It affects 1 product.

Products include Freebsd Freebsd.

How do I fix CVE-2021-29626?

No fix has been published for CVE-2021-29626 yet. Limit exposure of the affected software until one is available.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2021-29626 being exploited?

There is no known exploitation of CVE-2021-29626 in the wild and no public exploit code.

All Freebsd Freebsd vulnerabilities

Sources

Also known as GHSA-h9f8-7jjc-4hg6.