CVE-2024-21626 | runc container breakout through process.cwd trickery and leaked fds

Exp

runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. In runc 1.1.11 and earlier, due to an internal file descriptor leak, an attacker could cause a newly-spawned container process (from runc exec) to have a working directory in the host filesystem namespace, allowing for a container escape by giving access to the host filesystem ("attack 2"). The same attack could be used by a malicious image to allow a container process to gain access to the host filesystem through runc run ("attack 1"). Variants of attacks 1 and 2 could be also be used to overwrite semi-arbitrary host binaries, allowing for complete container escapes ("attack 3a" and "attack 3b"). runc 1.1.12 includes patches for this issue.

Published: 2024-01-31 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-21626 is rated High Exploit Risk (88.2/100): CVSS High severity, with high exploitation likelihood (EPSS 16.78%, 97th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +12.18% over the last day, indicating growing attacker interest. 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-2024-21626

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

Exploit prediction scoring system (EPSS) score for CVE-2024-21626

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 4.59% 16.78% +12.18%
2 2026-06-12 4.71% 4.59% -0.12%
3 2026-06-11 — 4.71% —

Full EPSS history (141 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-21626

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H 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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 6.0 [email protected]
8.6 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H 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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 6.0 [email protected]

Weakness enumeration for CVE-2024-21626

GitHub Security Advisory for CVE-2024-21626

GHSA-xr7r-f8xq-vfvv · Severity: high · Ecosystem: go — runc vulnerable to container breakout through process.cwd trickery and leaked fds

OS Trackers for CVE-2024-21626

vendor priority summary link
alpine — CVE-2024-21626: 1 source package rows (runc); 22 state rows across 5 repos (3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 5, open 17. https://security.alpinelinux.org/vuln/CVE-2024-21626
debian not yet assigned CVE-2024-21626 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-2024-21626
gentoo normal CVE-2024-21626: 1 GLSA(s) (202408-25), 1 atom(s) (app-containers/runc); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-21626
redhat high — https://access.redhat.com/security/cve/CVE-2024-21626
suse high CVE-2024-21626 severity important: SUSE including 292 source package names (1.2.3-2.2.132:runc-1.1.12-150000.61.2, 1.2.3-3.2.153:runc-1.1.12-150000.61.2, …), 581 product×package rows across 291 product lines (Container rancher/elemental-teal-rt/5.4, Container rancher/elemental-teal/5.4, … (291 product lines)): Fixed 358, Known Affected 195, Known Not Affected 28. https://www.suse.com/security/cve/CVE-2024-21626/
ubuntu high CVE-2024-21626 high priority: Ubuntu including 1 source packages (runc), 9 status rows across 9 suites (bionic, focal, jammy, lunar, mantic, noble, trusty, upstream, xenial): released 5, ignored 2, not-affected 2. https://ubuntu.com/security/CVE-2024-21626

Affected software / configurations for CVE-2024-21626

Vendor Product Version Raw CPE
linuxfoundation runc < 1.1.12 cpe:2.3:a:linuxfoundation:runc:*:*:*:*:*:*:*:*
fedoraproject fedora 39 cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*

References for CVE-2024-21626

URL Tags
http://packetstormsecurity.com/files/176993/runc-1.1.11-File-Descriptor-Leak-Privilege-Escalation.html Exploit Third Party Advisory VDB Entry
http://www.openwall.com/lists/oss-security/2024/02/01/1 Mailing List
http://www.openwall.com/lists/oss-security/2024/02/02/3 Mailing List
https://github.com/opencontainers/runc/commit/02120488a4c0fc487d1ed2867e901eeed7ce8ecf Patch
https://github.com/opencontainers/runc/releases/tag/v1.1.12 Release Notes
https://github.com/opencontainers/runc/security/advisories/GHSA-xr7r-f8xq-vfvv Exploit Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/02/msg00005.html
https://lists.fedoraproject.org/archives/list/[email protected]/message/2NLXNE23Q5ESQUAI22Z7A63JX2WMPJ2J/
https://lists.fedoraproject.org/archives/list/[email protected]/message/SYMO3BANINS6RGFQFKPRG4FIOJ7GWYTL/ Mailing List
https://www.vicarius.io/vsociety/posts/leaky-vessels-part-1-cve-2024-21626
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