Vulnerability in Libcap Project
CVE-2026-4878
A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the `cap_set_file()` function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (2.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 2.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.001 · change: -0.001
Affected products
- Libcap Project
- Red Hat Cost Management 4 — versions 1780946239, 1783539156
- Red Hat Cost Management Metrics Operator 4 — versions 1780946239, 1783539156
- Red Hat Ai Inference Server 3.2 — versions 1780681984
- Red Hat Ai Inference Server 3.3 — versions 1782352950, 1782352847, 1782352919
- Red Hat Discovery 2 — versions 1778101579, 1782159791, 1778156756
- Red Hat Enterprise Linux 10 — versions 0:2.69-7.el10_2.1, 0:2.69-7.el10_1.1
- Red Hat Enterprise Linux 10.0 Extended Update Support — versions 0:2.69-7.el10_0.1
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Weakness classification (CWE)
References
- access.redhat.com/errata/RHSA-2026:12423 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:12441 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:13285 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:7473 (vendor-advisory, Vendor Advisory)
- access.redhat.com/security/cve/CVE-2026-4878 (vdb-entry, Vendor Advisory)
- bugzilla.redhat.com/show_bug.cgi (Permissions Required)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking, Issue Tracking, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-4878?
- CVE-2026-4878 is a medium-severity vulnerability in Libcap Project, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 6.7/10. Published 2026-04-09.
- How severe is CVE-2026-4878?
- Medium severity. CVSS v3 base score is 6.7 out of 10.