# CVE-2025-52881: runc: LSM labels can be bypassed with malicious config using dummy procfs files > Attackers can bypass LSM security labels in runc by misdirecting procfs writes via race conditions, requiring an upgrade to patched versions. - **Severity:** High 7.3 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 6 Nov 2025 - **Updated:** 6 Nov 2025 - **Also known as:** ALSA-2025:21220, ALSA-2025:21702, ALSA-2025:23543, AZL-69824, AZL-69826, AZL-70586, BELL-CVE-2025-52881, CLEANSTART-2026-MT88967, CLEANSTART-2026-QO04531, CLEANSTART-2026-RA97554, CLEANSTART-2026-RD73080, CLSA-2025-1766050574, DEBIAN-CVE-2025-52881, ECHO-4e92-dcc8-abdf, GHSA-cgrx-mc8f-2prm, GO-2025-4098, MINI-227j-4f5c-gw3h, MINI-27fc-vm57-3wff, MINI-2prg-2fwp-hmhr, MINI-379r-vmp5-828w, MINI-3ch9-64mf-2mrc, MINI-3mj7-h29w-ph56, MINI-3w7g-cv64-6vm2, MINI-56c9-8fv4-mwj2, MINI-5jg6-mrjv-p8jp, MINI-5x66-34qq-q22q, MINI-6288-6r3g-7j2r, MINI-697q-h9mm-m7hm, MINI-6r3c-p8gp-qrmr, MINI-6xj5-vgr2-c8gh, MINI-77px-vm35-4v4h, MINI-7hv2-v256-vxcv, MINI-7r2r-9cgr-4vf9, MINI-833m-q65x-r4qj, MINI-982f-rx2p-gfgj, MINI-c2m5-p76g-9q4v, MINI-c2mm-v9xp-6rx3, MINI-cfhf-jvvg-788g, MINI-chhh-hw5w-fj5m, MINI-cqx6-v6mf-2hfm, MINI-h5vc-6wr2-r8rv, MINI-hg5x-5qvv-mhr6, MINI-hp4q-52mg-xv5f, MINI-hw8r-33rf-j9j3, MINI-jm25-455j-68gv, MINI-jv7r-m6w8-9c96, MINI-m283-2mf8-vfh5, MINI-mrrm-454c-475x, MINI-p538-r5f6-px33, MINI-p9fx-3462-476f, MINI-qf85-r74g-4wpg, MINI-rjhc-m36h-435j, MINI-rr5q-f4p2-96fv, MINI-v3x8-4fcc-38rr, MINI-vf9g-3x39-mpx7, MINI-vh7x-r6jp-jx5f, MINI-wrgr-hhrm-2w9p, MINI-x8vj-wf8m-q2jc, MINI-xh58-xccr-83vj, RHSA-2025:21220, RHSA-2025:21633, RHSA-2025:21634, RHSA-2025:21702, RHSA-2025:23543, RHSA-2026:2975, RLSA-2025:21220, RLSA-2025:21702, RLSA-2025:23543, SUSE-SU-2025:4074-1, SUSE-SU-2025:4075-1, SUSE-SU-2025:4076-1, UBUNTU-CVE-2025-52881, openSUSE-SU-2025:15721-1, openSUSE-SU-2025:15843-1 ## What is CVE-2025-52881? CVE-2025-52881 is a high-severity vulnerability in opencontainers runc, published on 6 Nov 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. ### Official description runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7, 1.3.2 and 1.4.0-rc.2, an attacker can trick runc into misdirecting writes to /proc to other procfs files through the use of a racing container with shared mounts (we have also verified this attack is possible to exploit using a standard Dockerfile with docker buildx build as that also permits triggering parallel execution of containers with custom shared mounts configured). This redirect could be through symbolic links in a tmpfs or theoretically other methods such as regular bind-mounts. While similar, the mitigation applied for the related CVE, CVE-2019-19921, was fairly limited and effectively only caused runc to verify that when LSM labels are written they are actually procfs files. This issue is fixed in versions 1.2.8, 1.3.3, and 1.4.0-rc.3. Weakness: CWE-61 (UNIX Symbolic Link (Symlink) Following), CWE-363 (Race Condition Enabling Link Following) ## Which versions are affected by CVE-2025-52881? 10 open source packages ship an affected version, including github.com/opencontainers/runc and github.com/opencontainers/selinux. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/opencontainers/runc` | Go | All versions | 1.2.8, 1.3.3, 1.4.0-rc.3 | | `github.com/opencontainers/runc` | Go | All versions | 1.2.8 | | `github.com/opencontainers/runc` | Go | All versions | 1.2.8 | | `github.com/opencontainers/runc` | Go | From 1.3.0-rc.1 | 1.3.3 | | `github.com/opencontainers/runc` | Go | From 1.3.0-rc.1 | 1.3.3 | | `github.com/opencontainers/runc` | Go | From 1.4.0-rc.1 | 1.4.0-rc.3 | | `github.com/opencontainers/runc` | Go | From 1.4.0-rc.1 | 1.4.0-rc.3 | | `github.com/opencontainers/selinux` | Go | All versions | 1.13.0 | | `github.com/opencontainers/selinux` | Go | All versions | 1.13.0 | | `github.com/opencontainers/selinux` | Go | All versions | 1.13.0 | | `podman-docker` | AlmaLinux:10 | All versions | 7:5.6.0-6.el10_1 | | `aardvark-dns` | AlmaLinux:8 | All versions | 2:1.10.1-2.module_el8.10.0+3909+6e1c1eb7 | | `aardvark-dns` | AlmaLinux:8 | All versions | 2:1.10.1-2.module_el8.10.0+4023+db236c53 | | `aardvark-dns` | AlmaLinux:8 | All versions | 2:1.10.1-2.module_el8.10.0+4047+545787c4 | | `aardvark-dns` | AlmaLinux:8 | All versions | 2:1.10.1-2.module_el8.10.0+4089+ce72bbbe | | `buildah` | AlmaLinux:8 | All versions | 2:1.33.13-1.module_el8.10.0+4082+f7f0c95e | | `buildah` | AlmaLinux:8 | All versions | 2:1.33.13-1.module_el8.10.0+4089+ce72bbbe | | `buildah-tests` | AlmaLinux:8 | All versions | 2:1.33.13-1.module_el8.10.0+4089+ce72bbbe | | `cockpit-podman` | AlmaLinux:8 | All versions | 84.1-1.module_el8.10.0+4016+efd18bf8 | | `conmon` | AlmaLinux:8 | All versions | 3:2.1.10-1.module_el8.10.0+3970+8445edf6 | | `conmon` | AlmaLinux:8 | All versions | 3:2.1.10-1.module_el8.10.0+4068+0e21408f | | `container-selinux` | AlmaLinux:8 | All versions | 2:2.229.0-2.module_el8.10.0+3909+6e1c1eb7 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 1:1.4.0-6.module_el8.10.0+4016+efd18bf8 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 1:1.4.0-6.module_el8.10.0+4047+545787c4 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 1:1.4.0-6.module_el8.10.0+4068+0e21408f | | `containers-common` | AlmaLinux:8 | All versions | 2:1-82.module_el8.10.0+3876+e55593a8 | | `containers-common` | AlmaLinux:8 | All versions | 2:1-82.module_el8.10.0+3901+4b80ecd7 | | `containers-common` | AlmaLinux:8 | All versions | 2:1-82.module_el8.10.0+4047+545787c4 | | `containers-common` | AlmaLinux:8 | All versions | 2:1-82.module_el8.10.0+4089+ce72bbbe | | `crit` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3845+87b84552 | | `crit` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3858+6ad51f9f | | `crit` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3901+4b80ecd7 | | `crit` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+4068+0e21408f | | `criu` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3876+e55593a8 | | `criu` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3909+6e1c1eb7 | | `criu` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3926+f12484f5 | | `criu` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+4089+ce72bbbe | | `criu-devel` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+3858+6ad51f9f | | `criu-devel` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+4016+efd18bf8 | | `criu-devel` | AlmaLinux:8 | All versions | 3.18-5.module_el8.10.0+4068+0e21408f | Products: Linuxfoundation Runc. ## How do I fix CVE-2025-52881? Upgrade github.com/opencontainers/runc to a fixed version for your release line: 1.2.8, 1.3.3 or 1.4.0-rc.3. ## Is CVE-2025-52881 being exploited? There is no known exploitation of CVE-2025-52881 in the wild and no public exploit code. Public exploit code: - Workaround for CVE-2025-52881: Fixes Docker/Podman breakage in Proxmox LXC containers caused by AppArmor incompatibility with runc 1.2.7+. Universal wrapper for community-scripts with automatic AppArmor configuration. (github_poc): https://github.com/jq6l43d1/proxmox-lxc-docker-fix ## Other vulnerabilities in opencontainers runc - [CVE-2025-52565](https://insights.sbomify.com/CVE-2025-52565/): container escape due to /dev/console mount and related races (high 8.4) - [CVE-2025-31133](https://insights.sbomify.com/CVE-2025-31133/): runc container escape via "masked path" abuse due to mount race conditions (high 7.3) - [CVE-2023-28642](https://insights.sbomify.com/CVE-2023-28642/): AppArmor bypass with symlinked /proc in runc (medium 6.1) - [CVE-2023-25809](https://insights.sbomify.com/CVE-2023-25809/): rootless: `/sys/fs/cgroup` is writable when cgroupns isn't unshared in runc (medium 5.0) - [CVE-2024-45310](https://insights.sbomify.com/CVE-2024-45310/): runc can be confused to create empty files/directories on the host (low 3.6) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-52881 and fix it if it is affected. What it is: CVE-2025-52881 is a high-severity vulnerability in opencontainers runc, published on 6 Nov 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2025-52881 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/opencontainers/runc (Go): affected all versions; fixed in 1.2.8, 1.3.3, 1.4.0-rc.3 - github.com/opencontainers/runc (Go): affected all versions; fixed in 1.2.8 - github.com/opencontainers/runc (Go): affected all versions; fixed in 1.2.8 - github.com/opencontainers/runc (Go): affected from 1.3.0-rc.1; fixed in 1.3.3 - github.com/opencontainers/runc (Go): affected from 1.3.0-rc.1; fixed in 1.3.3 - github.com/opencontainers/runc (Go): affected from 1.4.0-rc.1; fixed in 1.4.0-rc.3 - github.com/opencontainers/runc (Go): affected from 1.4.0-rc.1; fixed in 1.4.0-rc.3 - github.com/opencontainers/selinux (Go): affected all versions; fixed in 1.13.0 - github.com/opencontainers/selinux (Go): affected all versions; fixed in 1.13.0 - github.com/opencontainers/selinux (Go): affected all versions; fixed in 1.13.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2025-52881/ (Markdown: https://insights.sbomify.com/CVE-2025-52881/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-52881 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-52881 - OSV: https://osv.dev/vulnerability/CVE-2025-52881 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-52881/ Summaries are generated and may contain mistakes; the official description above is the record.