CVE-2026-4878: Time-of-check Time-of-use (TOCTOU) Race Condition in Red Hat Red Hat Enterprise Linux 10
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.
AI Analysis
Technical Summary
CVE-2026-4878 is a TOCTOU race condition vulnerability in the cap_set_file() function of the libcap library used by Red Hat Enterprise Linux 9 and 10. An unprivileged local attacker with write access to a parent directory can exploit this flaw to redirect capability changes to arbitrary files, enabling unauthorized modification of file capabilities. This can result in privilege escalation by injecting or removing capabilities from executables. Red Hat has issued security advisories RHSA-2026:12423 and RHSA-2026:12441 providing updated libcap packages that fix this vulnerability.
Potential Impact
Successful exploitation allows local unprivileged users to escalate privileges by manipulating file capabilities on executables, potentially gaining unauthorized elevated access. The CVSS v3.1 base score is 6.7 (medium severity) with high impact on confidentiality, integrity, and availability. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released official security updates for libcap that address this TOCTOU race condition. Users should apply the updated libcap packages as detailed in Red Hat advisories RHSA-2026:12423 for RHEL 10 and RHSA-2026:12441 for RHEL 9. Instructions for applying these updates are available at https://access.redhat.com/articles/11258. Applying these patches fully mitigates the vulnerability.
CVE-2026-4878: Time-of-check Time-of-use (TOCTOU) Race Condition in Red Hat Red Hat Enterprise Linux 10
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.
CVSS v3.1
Score 6.7medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-4878 is a TOCTOU race condition vulnerability in the cap_set_file() function of the libcap library used by Red Hat Enterprise Linux 9 and 10. An unprivileged local attacker with write access to a parent directory can exploit this flaw to redirect capability changes to arbitrary files, enabling unauthorized modification of file capabilities. This can result in privilege escalation by injecting or removing capabilities from executables. Red Hat has issued security advisories RHSA-2026:12423 and RHSA-2026:12441 providing updated libcap packages that fix this vulnerability.
Potential Impact
Successful exploitation allows local unprivileged users to escalate privileges by manipulating file capabilities on executables, potentially gaining unauthorized elevated access. The CVSS v3.1 base score is 6.7 (medium severity) with high impact on confidentiality, integrity, and availability. No known exploits in the wild have been reported at this time.
Mitigation Recommendations
Red Hat has released official security updates for libcap that address this TOCTOU race condition. Users should apply the updated libcap packages as detailed in Red Hat advisories RHSA-2026:12423 for RHEL 10 and RHSA-2026:12441 for RHEL 9. Instructions for applying these updates are available at https://access.redhat.com/articles/11258. Applying these patches fully mitigates the vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-03-26T06:32:41.308Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-4878","vendor":"Red Hat"}]
Threat ID: 69d7ce5e1cc7ad14dae8f92c
Added to database: 04/09/2026, 16:05:50 UTC
Last enriched: 07/24/2026, 22:35:59 UTC
Last updated: 07/31/2026, 19:30:16 UTC
Views: 219
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