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…
- Published
- Updated
- Reserved
- Assigned by
- redhat
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.
Timeline
ID reserved
By redhat
- 11 months later
· 11 months later
Published
- 24 months later
· 24 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.78% · top 44% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.0.
Weakness
Affected products
kernel
- affected Not Known
References (7)
- https://www.openwall.com/lists/oss-security/2021/10/20/2 (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.redhat.com/show_bug.cgi?id=2015046 (opens in a new tab)x_refsource_MISCx_transferred
- https://access.redhat.com/security/cve/CVE-2021-3864 (opens in a new tab)x_refsource_MISCx_transferred
- https://lore.kernel.org/all/20211221021744.864115-1-longman%40redhat.com/ (opens in a new tab)x_refsource_MISCx_transferred
- https://lore.kernel.org/lkml/20211228170910.623156-1-wander%40redhat.com/ (opens in a new tab)x_refsource_MISCx_transferred
- https://lore.kernel.org/all/20211226150310.GA992%401wt.eu/ (opens in a new tab)x_refsource_MISCx_transferred
- https://security-tracker.debian.org/tracker/CVE-2021-3864 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-3864)Record last updated .