CVE-2021-3864
highpriority · track · 38EPSS 0.008 · 56 %ileexploit · PoCDEEUUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–7
weaknesses
The CWE weakness classes this flaw belongs to.
exploits (1)
Public proof-of-concept and weaponised exploit code.
- walac/cve-2021-3864Test for cve-2021-3864PoC · poc_in_github
affected products (11)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2022-1257Linux Kernel: Mehrere SchwachstellenDeutsch2022-09-01csaf · cert_bundDE
Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um seine Privilegien zu erhöhen und einen Denial of Service Zustand zu verursachen.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (25)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/CVE-2021-3864cnnvd
- https://bugzilla.redhat.com/show_bug.cgi?id=2015046cnnvd
- https://cxsecurity.com/cveshow/CVE-2021-3864/cnnvd
- https://lore.kernel.org/all/20211221021744.864115-1-longman%40redhat.com/cnnvd
- https://lore.kernel.org/all/20211221021744.864115-1-longman@redhat.com/cnnvd
- https://lore.kernel.org/all/20211226150310.GA992%401wt.eu/cnnvd
- https://lore.kernel.org/all/20211226150310.GA992@1wt.eu/cnnvd
- https://lore.kernel.org/lkml/20211228170910.623156-1-wander%40redhat.com/cnnvd
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