CVE-2023-25809 | rootless: `/sys/fs/cgroup` is writable when cgroupns isn't unshared in runc

Exp

runc is a CLI tool for spawning and running containers according to the OCI specification. In affected versions it was found that rootless runc makes `/sys/fs/cgroup` writable in following conditons: 1. when runc is executed inside the user namespace, and the `config.json` does not specify the cgroup namespace to be unshared (e.g.., `(docker|podman|nerdctl) run --cgroupns=host`, with Rootless Docker/Podman/nerdctl) or 2. when runc is executed outside the user namespace, and `/sys` is mounted with `rbind, ro` (e.g., `runc spec --rootless`; this condition is very rare). A container may gain the write access to user-owned cgroup hierarchy `/sys/fs/cgroup/user.slice/...` on the host . Other users's cgroup hierarchies are not affected. Users are advised to upgrade to version 1.1.5. Users unable to upgrade may unshare the cgroup namespace (`(docker|podman|nerdctl) run --cgroupns=private)`. This is the default behavior of Docker/Podman/nerdctl on cgroup v2 hosts. or add `/sys/fs/cgroup` to `maskedPaths`.

Published: 2023-03-29 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-25809 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.33%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2023-25809

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2023-25809

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.33% +0.29%
2 2025-11-21 0.06% 0.03% -0.03%
3 2025-11-18 — 0.06% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-25809

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 3.1 MEDIUM
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:L Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 0.8 3.7 [email protected]
6.3 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.0 3.7 [email protected]

Weakness enumeration for CVE-2023-25809

GitHub Security Advisory for CVE-2023-25809

GHSA-m8cg-xc2p-r3fc · Severity: low · Ecosystem: go — rootless: `/sys/fs/cgroup` is writable when cgroupns isn't unshared in runc

OS Trackers for CVE-2023-25809

vendor priority summary link
alpine medium CVE-2023-25809: 1 source package rows (runc); 22 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 9, open 13. https://security.alpinelinux.org/vuln/CVE-2023-25809
debian not yet assigned CVE-2023-25809 not yet assigned priority: Debian including 1 source packages (runc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-25809
gentoo normal CVE-2023-25809: 1 GLSA(s) (202408-25), 1 atom(s) (app-containers/runc); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-25809
redhat medium — https://access.redhat.com/security/cve/CVE-2023-25809
suse medium CVE-2023-25809 severity moderate: SUSE including 246 source package names (1.2.3-2.2.63:runc-1.1.5-150000.41.1, 1.2.3-3.2.78:runc-1.1.5-150000.41.1, …), 549 product×package rows across 297 product lines (Container rancher/elemental-teal-iso/5.4, Container rancher/elemental-teal-rt/5.4, … (297 product lines)): Fixed 382, Known Affected 147, Known Not Affected 20. https://www.suse.com/security/cve/CVE-2023-25809/
ubuntu medium CVE-2023-25809 medium priority: Ubuntu including 1 source packages (runc), 8 status rows across 8 suites (bionic, focal, jammy, kinetic, lunar, trusty, upstream, xenial): released 7, ignored 1. https://ubuntu.com/security/CVE-2023-25809

Affected software / configurations for CVE-2023-25809

Vendor Product Version Raw CPE
linuxfoundation runc < 1.1.5 cpe:2.3:a:linuxfoundation:runc:*:*:*:*:*:*:*:*

References for CVE-2023-25809

cvelogic Threat Intelligence