Description
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.
Affected products
linuxfoundation: runc
References5
- github.com/opencontainers/runc/commit/1a30a8f3d921acbbb6a4bb7e9… Patch
- github.com/opencontainers/runc/commit/5d7b2424072449872d1cd0c93… Patch
- github.com/opencontainers/runc/commit/8476df83b534a2522b878c050… Patch
- github.com/opencontainers/runc/commit/db19bbed5348847da433faa9d… Patch
- github.com/opencontainers/runc/security/advisories/GHSA-9493-h2… MitigationPatchThird Party Advisory
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: NVD
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H - CVSS 4.0
-
7.3
HIGH
Score source: CNA
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 1% percentile: 70 · as of 10 November 2026
- CWE
- CWE-61CWE-363
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.