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
A TOCTOU race condition exists in the cap_set_file() function of libcap on Red Hat Enterprise Linux 10. An unprivileged local attacker with write permissions to a parent directory can exploit this flaw to redirect file capability updates to attacker-controlled files. This can cause unintended executables to gain or lose capabilities, enabling privilege escalation. The vulnerability is tracked as CVE-2026-4878 with a CVSS 3.1 base score of 6.7 (AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H). The vendor advisory is published but does not specify patch availability or mitigation details.
Potential Impact
Successful exploitation allows a local unprivileged user to escalate privileges by injecting or stripping capabilities from executables via a race condition in libcap. This can compromise confidentiality, integrity, and availability of the system. The impact is rated medium severity with high impact on confidentiality, integrity, and availability according to the CVSS vector. No known active exploitation has been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-4878 for current remediation guidance. Until an official fix is available, restrict write access to parent directories of files that may be targeted by this vulnerability to trusted users only. Monitor Red Hat communications for updates on patches or workarounds.
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
A TOCTOU race condition exists in the cap_set_file() function of libcap on Red Hat Enterprise Linux 10. An unprivileged local attacker with write permissions to a parent directory can exploit this flaw to redirect file capability updates to attacker-controlled files. This can cause unintended executables to gain or lose capabilities, enabling privilege escalation. The vulnerability is tracked as CVE-2026-4878 with a CVSS 3.1 base score of 6.7 (AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H). The vendor advisory is published but does not specify patch availability or mitigation details.
Potential Impact
Successful exploitation allows a local unprivileged user to escalate privileges by injecting or stripping capabilities from executables via a race condition in libcap. This can compromise confidentiality, integrity, and availability of the system. The impact is rated medium severity with high impact on confidentiality, integrity, and availability according to the CVSS vector. No known active exploitation has been reported.
Mitigation Recommendations
Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-4878 for current remediation guidance. Until an official fix is available, restrict write access to parent directories of files that may be targeted by this vulnerability to trusted users only. Monitor Red Hat communications for updates on patches or workarounds.
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: 4/9/2026, 4:05:50 PM
Last enriched: 4/9/2026, 4:20:57 PM
Last updated: 4/9/2026, 5:11:41 PM
Views: 4
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