CVE-2021-3864 Privilege escalation in kernel
An unprivileged local user can escalate privileges by exploiting SUID binary core dump handling when core_pattern is relative.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-3864?
CVE-2021-3864 is a high-severity vulnerability in Debian Debian Linux, published on 26 Aug 2022. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A flaw was found in the way the dumpable flag setting was handled when certain SUID binaries executed its descendants. The prerequisite is a SUID binary that sets real UID equal to effective UID, and real GID equal to effective GID. The descendant will then have a dumpable value set to 1. As a result, if the descendant process crashes and core_pattern is set to a relative value, its core dump is stored in the current directory with uid:gid permissions. An unprivileged local user with eligible root SUID binary could use this flaw to place core dumps into root-owned directories, potentially resulting in escalation of privileges.
Weakness: CWE-284
Which versions are affected by CVE-2021-3864?
It affects 3 products.
Products include Debian Debian Linux, Linux kernel, Redhat Enterprise Linux.
How do I fix CVE-2021-3864?
Apply the vendor's patch.
Is CVE-2021-3864 being exploited?
There is no known exploitation of CVE-2021-3864 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2021-3864, GHSA-9682-f2fr-3h46, ROOT-OS-DEBIAN-11-CVE-2021-3864, ROOT-OS-DEBIAN-12-CVE-2021-3864, ROOT-OS-DEBIAN-13-CVE-2021-3864, ROOT-OS-UBUNTU-2204-CVE-2021-3864 and 2 more.