CVE-2026-4878
HIGHCVSS 7/10EPSS 0.21%
Last modified
CVE-2026-4878 is a high-severity vulnerability rated 7/10 on the CVSS scale. 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. EPSS estimates a 0.21% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Libcap Project | Libcap | All versions |
| Redhat | Openshift Container Platform | 4.0 |
| Redhat | Enterprise Linux | 8.0 |
| Redhat | Enterprise Linux | 9.0 |
| Redhat | Enterprise Linux | 10.0 |
References
- https://access.redhat.com/errata/RHSA-2026:7473Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-4878Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2447554Permissions Required
- https://bugzilla.redhat.com/show_bug.cgi?id=2451615Issue Tracking, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/04/07/14Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/07/4Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/08/9Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/09/5Exploit, Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2026/04/09/6Exploit, Mailing List, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:7473Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-4878Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2451615Issue Tracking, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is 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.
How severe is CVE-2026-4878?
CVE-2026-4878 has a CVSS score of 7/10 (HIGH severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.
How do I fix CVE-2026-4878?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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