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CVE-2025-31133

runc container escape via "masked path" abuse due to mount race conditions

HIGH
7.8
CVSS Score
Published: November 6, 2025 at 06:47 PM UTC
Updated: October 7, 2026 at 09:10 PM UTC
2 products affected across 2 vendorsRuncRunc

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Severity
HIGH7.8
Exploit prediction
EPSS 1%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Runc· Linuxfoundation
95%
v < 1.2.81.3.0 ≤ v < 1.3.31.4.0 rc11.4.0 rc2
Affected range stops below 1.2.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.3.3, so it looks safe — our inference, not a vendor statement
Runc· Opencontainers
60%
v ≤ 1.4.0-rc.3v < 1.2.8v < 1.3.3
Affected range stops below 1.2.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.3.3, so it looks safe — our inference, not a vendor statement

References (5)

x_refsource_CONFIRMMitigationPatchThird Party Advisory
Source: cverecord
https://github.com/opencontainers/runc/security/advisories/GHSA-9493-h29p-rfm2
x_refsource_MISCPatch
Source: cverecord
https://github.com/opencontainers/runc/commit/1a30a8f3d921acbbb6a4bb7e99da2c05f8d48522
x_refsource_MISCPatch
Source: cverecord
https://github.com/opencontainers/runc/commit/5d7b2424072449872d1cd0c937f2ca25f418eb66
x_refsource_MISCPatch
Source: cverecord
https://github.com/opencontainers/runc/commit/8476df83b534a2522b878c0507b3491def48db9f
x_refsource_MISCPatch
Source: cverecord
https://github.com/opencontainers/runc/commit/db19bbed5348847da433faa9d69e9f90192bfa64

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGH[email protected]
Attack Vector
LOCAL
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-61CWE-363

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