CVE-2021-3864

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.

Affected

kernel

CVSS v3.1 NVD

7.0 HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.77% chance of exploitation in the next 30 days, 55th percentile

Published

2022-08-26

Updated

2024-08-03

Proof-of-concept exploits (2)

• https://www.openwall.com/lists/oss-security/2021/10/20/2
• walac/cve-2021-38640★ · 2022-04-01

Security advisories

• https://access.redhat.com/security/cve/CVE-2021-3864
• https://bugzilla.redhat.com/show_bug.cgi?id=2015046
• https://security-tracker.debian.org/tracker/CVE-2021-3864

References

• CVE Record
• NVD entry