Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | - |
| Debian | Debian Linux | 10.0 |
| Redhat | Enterprise Linux | 6.0 |
Related Weaknesses (CWE)
References
- https://access.redhat.com/security/cve/CVE-2021-3864Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2015046Issue TrackingPatchThird Party Advisory
- https://lore.kernel.org/all/20211221021744.864115-1-longman%40redhat.com/
- https://lore.kernel.org/all/20211226150310.GA992%401wt.eu/
- https://lore.kernel.org/lkml/20211228170910.623156-1-wander%40redhat.com/
- https://security-tracker.debian.org/tracker/CVE-2021-3864Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/10/20/2ExploitMailing ListThird Party Advisory
- https://access.redhat.com/security/cve/CVE-2021-3864Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2015046Issue TrackingPatchThird Party Advisory
- https://lore.kernel.org/all/20211221021744.864115-1-longman%40redhat.com/
- https://lore.kernel.org/all/20211226150310.GA992%401wt.eu/
- https://lore.kernel.org/lkml/20211228170910.623156-1-wander%40redhat.com/
- https://security-tracker.debian.org/tracker/CVE-2021-3864Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/10/20/2ExploitMailing ListThird Party Advisory
FAQ
What is CVE-2021-3864?
CVE-2021-3864 is a vulnerability with a CVSS score of 7.0 (HIGH). 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 ...
How severe is CVE-2021-3864?
CVE-2021-3864 has been rated HIGH with a CVSS base score of 7.0/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-3864?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel, Debian Debian Linux, Redhat Enterprise Linux.