# CVE-2026-4878: Libcap: libcap: privilege escalation via toctou race condition in cap_set_file() CVE-2026-4878 is fixed in 6 products on 1 platform, first by RHSA-2026:19456, released April 6, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-4878 - Priority: High - CVSS: 7.0 (Moderate) - EPSS: 0.0021 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Apr 6, 2026 - Weakness: Time-of-check Time-of-use (TOCTOU) Race Condition - Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-4878 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | golang-kernel-pub-linux-libs-security-libcap-dev Ubuntu 25.10 (questing) | 1:2.75-7ubuntu2.2 | [golang-kernel-pub-linux-libs-security-libcap-dev 1:2.75-7ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-golang-kernel-pub-linux-libs-security-libcap-dev-1-2.75-7ubuntu2.2.md) | Apr 9, 2026 | | Linux | libcap RHEL 10 | 2.69-7.el10_0.1 | [RHSA-2026:19456](https://patchblox.com/security/data/fix/linux/rhsa-2026-19456.md) | Apr 6, 2026 | | Linux | libcap RHEL 8 | 0:2.48-6.el8_10.1 | [RHSA-2026:13285](https://patchblox.com/security/data/fix/linux/rhsa-2026-13285.md) | May 15, 2026 | | Linux | libcap RHEL 9 | 0:2.48-10.el9_8.1 | [RHSA-2026:19346](https://patchblox.com/security/data/fix/linux/rhsa-2026-19346.md) | May 15, 2026 | | Linux | libcap almalinux 10 | 2.69-7.el10_2.1 | [ALSA-2026:19130](https://patchblox.com/security/data/fix/linux/alsa-2026-19130.md) | May 19, 2026 | | Linux | libcap almalinux 8 | 2.48-6.el8_10.1 | [ALSA-2026:13285](https://patchblox.com/security/data/fix/linux/alsa-2026-13285.md) | May 4, 2026 | | Linux | libcap almalinux 9 | 2.48-10.el9_8.1 | [ALSA-2026:19346](https://patchblox.com/security/data/fix/linux/alsa-2026-19346.md) | May 19, 2026 | | Linux | libcap ol 10 | 0:2.69-7.el10_1.1 | [ELSA-2026-12423](https://patchblox.com/security/data/fix/linux/elsa-2026-12423.md) | Apr 30, 2026 | | Linux | libcap ol 8 | 0:2.48-6.el8_10.1 | [ELSA-2026-13285](https://patchblox.com/security/data/fix/linux/elsa-2026-13285.md) | May 5, 2026 | | Linux | libcap ol 9 | 0:2.48-10.el9_7.1 | [ELSA-2026-12441](https://patchblox.com/security/data/fix/linux/elsa-2026-12441.md) | Apr 30, 2026 | | Linux | libcap opensuse-leap 16.0 | 2.73-160000.3.1 | [OPENSUSE-SU-2026:20613-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20613-1.md) | Apr 22, 2026 | | Linux | libcap rocky 10 | 0:2.69-7.el10_1.1 | [RLSA-2026:19130](https://patchblox.com/security/data/fix/linux/rlsa-2026-19130.md) | May 29, 2026 | | Linux | libcap rocky 8 | 0:2.48-6.el8_10.1 | [RLSA-2026:13285](https://patchblox.com/security/data/fix/linux/rlsa-2026-13285.md) | May 6, 2026 | | Linux | libcap rocky 9 | 0:2.48-10.el9_7.1 | [RLSA-2026:19346](https://patchblox.com/security/data/fix/linux/rlsa-2026-19346.md) | May 20, 2026 | | Linux | libcap sles 15.6 | 2.63-150400.3.6.1 | [SUSE-SU-2026:1432-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1432-1.md) | Apr 17, 2026 | | Linux | libcap sles 15.7 | 2.63-150400.3.6.1 | [SUSE-SU-2026:1432-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-1432-1.md) | Apr 17, 2026 | | Linux | libcap-devel RHEL 8 | 0:2.48-6.el8_10.1 | [RHSA-2026:13285](https://patchblox.com/security/data/fix/linux/rhsa-2026-13285.md) | May 15, 2026 | | Linux | libcap-devel RHEL 9 | 0:2.48-10.el9_8.1 | [RHSA-2026:19346](https://patchblox.com/security/data/fix/linux/rhsa-2026-19346.md) | May 15, 2026 | | Linux | libcap-devel almalinux 10 | 2.69-7.el10_2.1 | [ALSA-2026:19130](https://patchblox.com/security/data/fix/linux/alsa-2026-19130.md) | May 19, 2026 | | Linux | libcap-devel almalinux 8 | 2.48-6.el8_10.1 | [ALSA-2026:13285](https://patchblox.com/security/data/fix/linux/alsa-2026-13285.md) | May 4, 2026 | | Linux | libcap-devel almalinux 9 | 2.48-10.el9_8.1 | [ALSA-2026:19346](https://patchblox.com/security/data/fix/linux/alsa-2026-19346.md) | May 19, 2026 | | Linux | libcap-devel ol 10 | 0:2.69-7.el10_1.1 | [ELSA-2026-12423](https://patchblox.com/security/data/fix/linux/elsa-2026-12423.md) | Apr 30, 2026 | | Linux | libcap-devel ol 8 | 0:2.48-6.el8_10.1 | [ELSA-2026-13285](https://patchblox.com/security/data/fix/linux/elsa-2026-13285.md) | May 5, 2026 | | Linux | libcap-devel ol 9 | 0:2.48-10.el9_7.1 | [ELSA-2026-12441](https://patchblox.com/security/data/fix/linux/elsa-2026-12441.md) | Apr 30, 2026 | | Linux | libcap2 Debian 12.15 (bookworm) | 1:2.66-4+deb12u3 | [DEBIAN-CVE-2026-4878](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4878.md) | Apr 9, 2026 | | Linux | libcap2 Debian 13.5 (trixie) | 1:2.75-10+deb13u1 | [DEBIAN-CVE-2026-4878](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4878.md) | Apr 9, 2026 | | Linux | libcap2 Debian 14 | 1:2.78-1 | [DEBIAN-CVE-2026-4878](https://patchblox.com/security/data/fix/linux/debian-cve-2026-4878.md) | Apr 9, 2026 | | Linux | libcap2 Ubuntu 18.04.6 LTS (bionic) | 1:2.25-1.2ubuntu0.1~esm2 | [libcap2 1:2.25-1.2ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libcap2-1-2.25-1.2ubuntu0.1-esm2.md) | Apr 9, 2026 | | Linux | libcap2 Ubuntu 20.04 LTS (focal) | 1:2.32-1ubuntu0.2+esm1 | [libcap2 1:2.32-1ubuntu0.2+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libcap2-1-2.32-1ubuntu0.2-esm1.md) | Apr 9, 2026 | | Linux | libcap2 Ubuntu 22.04.1 LTS (jammy) | 1:2.44-1ubuntu0.22.04.3 | [libcap2 1:2.44-1ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcap2-1-2.44-1ubuntu0.22.04.3.md) | Apr 30, 2026 | | Linux | libcap2 Ubuntu 24.04.5 LTS (noble) | 1:2.66-5ubuntu2.4 | [libcap2 1:2.66-5ubuntu2.4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcap2-1-2.66-5ubuntu2.4.md) | Apr 30, 2026 | | Linux | libcap2 Ubuntu 25.10 (questing) | 1:2.75-7ubuntu2.2 | [libcap2 1:2.75-7ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcap2-1-2.75-7ubuntu2.2.md) | Apr 30, 2026 | | Linux | libcap2-bin Ubuntu 18.04.6 LTS (bionic) | 1:2.25-1.2ubuntu0.1~esm2 | [libcap2-bin 1:2.25-1.2ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libcap2-bin-1-2.25-1.2ubuntu0.1-esm2.md) | Apr 9, 2026 | | Linux | libcap2-bin Ubuntu 20.04 LTS (focal) | 1:2.32-1ubuntu0.2+esm1 | [libcap2-bin 1:2.32-1ubuntu0.2+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libcap2-bin-1-2.32-1ubuntu0.2-esm1.md) | Apr 9, 2026 | | Linux | libcap2-bin Ubuntu 22.04.1 LTS (jammy) | 1:2.44-1ubuntu0.22.04.3 | [libcap2-bin 1:2.44-1ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcap2-bin-1-2.44-1ubuntu0.22.04.3.md) | Apr 30, 2026 | | Linux | libcap2-bin Ubuntu 24.04.5 LTS (noble) | 1:2.66-5ubuntu2.4 | [libcap2-bin 1:2.66-5ubuntu2.4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcap2-bin-1-2.66-5ubuntu2.4.md) | Apr 30, 2026 | | Linux | libcap2-bin Ubuntu 25.10 (questing) | 1:2.75-7ubuntu2.2 | [libcap2-bin 1:2.75-7ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcap2-bin-1-2.75-7ubuntu2.2.md) | Apr 30, 2026 | | Linux | libpam-cap Ubuntu 18.04.6 LTS (bionic) | 1:2.25-1.2ubuntu0.1~esm2 | [libpam-cap 1:2.25-1.2ubuntu0.1~esm2](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libpam-cap-1-2.25-1.2ubuntu0.1-esm2.md) | Apr 9, 2026 | | Linux | libpam-cap Ubuntu 20.04 LTS (focal) | 1:2.32-1ubuntu0.2+esm1 | [libpam-cap 1:2.32-1ubuntu0.2+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libpam-cap-1-2.32-1ubuntu0.2-esm1.md) | Apr 9, 2026 | | Linux | libpam-cap Ubuntu 22.04.1 LTS (jammy) | 1:2.44-1ubuntu0.22.04.3 | [libpam-cap 1:2.44-1ubuntu0.22.04.3](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libpam-cap-1-2.44-1ubuntu0.22.04.3.md) | Apr 30, 2026 | | Linux | libpam-cap Ubuntu 24.04.5 LTS (noble) | 1:2.66-5ubuntu2.4 | [libpam-cap 1:2.66-5ubuntu2.4](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libpam-cap-1-2.66-5ubuntu2.4.md) | Apr 30, 2026 | | Linux | libpam-cap Ubuntu 25.10 (questing) | 1:2.75-7ubuntu2.2 | [libpam-cap 1:2.75-7ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libpam-cap-1-2.75-7ubuntu2.2.md) | Apr 30, 2026 | --- Data as of 2026-11-08T06:59:42Z UTC. 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