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NVD / CVE Program· CNA GitHub_M

CVE-2025-31133: runc container escape via "masked path" abuse due to mount race conditions

Noroxi assessment

Priority: Monitor (action score 29/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.2% (FIRST EPSS); higher than 69.5% of all records.
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No special conditions are required; it is repeatable.
  • Fixed version: azl3 kubernetes 1.30.10-14 on Azure Linux 3.0 1.30.10-15; cbl2 kubernetes 1.28.4-19 on CBL Mariner 2.0 1.28.4-20; cbl2 moby-runc 1.1.9-9 on CBL Mariner 2.0 1.2.8-1.

Low priority for now. Upgrade to azl3 kubernetes 1.30.10-14 on Azure Linux 3.0 1.30.10-15; cbl2 kubernetes 1.28.4-19 on CBL Mariner 2.0 1.28.4-20; cbl2 moby-runc 1.1.9-9 on CBL Mariner 2.0 1.2.8-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.3 · v4.0—Proof of concept Fix available
Published
Nov 6, 2025
Updated
Oct 7, 2026
EPSS
1.2% · 69th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
29 / 40 · 7.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-31133

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  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxfoundationrunc

Using runc? Add it to your stack and be the first to know about CVEs like this one. (Docker)

Watch new CVEs for runc

When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or gets exploit code

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Your free account also gets you

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
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Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every Monday

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linuxfoundation runcbefore 1.2.8
  • linuxfoundation runc1.3.0 and later · before 1.3.3
  • linuxfoundation runc1.4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • opencontainers runc

    • < 1.2.8, >= 1.3.0-rc.1, < 1.3.3, >= 1.4.0-rc.1, <= 1.4.0-rc.3affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8aardvark-dnsbefore 2:1.10.1-2.module_el8.10.0+3909+6e1c1eb72:1.10.1-2.module_el8.10.0+3909+6e1c1eb7
AlmaLinux:8aardvark-dnsbefore 2:1.10.1-2.module_el8.10.0+4047+545787c42:1.10.1-2.module_el8.10.0+4047+545787c4
AlmaLinux:8aardvark-dnsbefore 2:1.10.1-2.module_el8.10.0+4023+db236c532:1.10.1-2.module_el8.10.0+4023+db236c53
AlmaLinux:8buildahbefore 2:1.33.12-2.module_el8.10.0+4023+db236c532:1.33.12-2.module_el8.10.0+4023+db236c53
AlmaLinux:8buildahbefore 2:1.33.12-2.module_el8.10.0+4047+545787c42:1.33.12-2.module_el8.10.0+4047+545787c4
AlmaLinux:8buildahbefore 2:1.33.12-2.module_el8.10.0+4016+efd18bf82:1.33.12-2.module_el8.10.0+4016+efd18bf8
AlmaLinux:8buildah-testsbefore 2:1.33.12-2.module_el8.10.0+4068+0e21408f2:1.33.12-2.module_el8.10.0+4068+0e21408f
AlmaLinux:8buildah-testsbefore 2:1.33.12-2.module_el8.10.0+4047+545787c42:1.33.12-2.module_el8.10.0+4047+545787c4
AlmaLinux:8cockpit-podmanbefore 84.1-1.module_el8.10.0+4016+efd18bf884.1-1.module_el8.10.0+4016+efd18bf8
AlmaLinux:8conmonbefore 3:2.1.10-1.module_el8.10.0+3970+8445edf63:2.1.10-1.module_el8.10.0+3970+8445edf6
AlmaLinux:8conmonbefore 3:2.1.10-1.module_el8.10.0+4068+0e21408f3:2.1.10-1.module_el8.10.0+4068+0e21408f
AlmaLinux:8container-selinuxbefore 2:2.229.0-2.module_el8.10.0+3909+6e1c1eb72:2.229.0-2.module_el8.10.0+3909+6e1c1eb7
AlmaLinux:8containernetworking-pluginsbefore 1:1.4.0-6.module_el8.10.0+4047+545787c41:1.4.0-6.module_el8.10.0+4047+545787c4
AlmaLinux:8containernetworking-pluginsbefore 1:1.4.0-6.module_el8.10.0+4016+efd18bf81:1.4.0-6.module_el8.10.0+4016+efd18bf8
AlmaLinux:8containernetworking-pluginsbefore 1:1.4.0-6.module_el8.10.0+4068+0e21408f1:1.4.0-6.module_el8.10.0+4068+0e21408f
AlmaLinux:8containers-commonbefore 2:1-82.module_el8.10.0+3901+4b80ecd72:1-82.module_el8.10.0+3901+4b80ecd7
AlmaLinux:8containers-commonbefore 2:1-82.module_el8.10.0+4047+545787c42:1-82.module_el8.10.0+4047+545787c4
AlmaLinux:8containers-commonbefore 2:1-82.module_el8.10.0+3876+e55593a82:1-82.module_el8.10.0+3876+e55593a8
AlmaLinux:8containers-commonbefore 2:1-82.module_el8.10.0+3970+8445edf62:1-82.module_el8.10.0+3970+8445edf6
AlmaLinux:8critbefore 3.18-5.module_el8.10.0+3858+6ad51f9f3.18-5.module_el8.10.0+3858+6ad51f9f
AlmaLinux:8critbefore 3.18-5.module_el8.10.0+4068+0e21408f3.18-5.module_el8.10.0+4068+0e21408f
AlmaLinux:8critbefore 3.18-5.module_el8.10.0+3901+4b80ecd73.18-5.module_el8.10.0+3901+4b80ecd7
AlmaLinux:8critbefore 3.18-5.module_el8.10.0+3845+87b845523.18-5.module_el8.10.0+3845+87b84552
AlmaLinux:8criubefore 3.18-5.module_el8.10.0+3876+e55593a83.18-5.module_el8.10.0+3876+e55593a8

+96

Same product

linuxfoundation: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-21626runc container breakout through process.cwd trickery and leaked fds
    40Plan
  • CVE-2021-30465runc before 1.0.0-rc95 allows a Container Filesystem Breakout via Directory Traversal.
    37Monitor
  • CVE-2025-52565container escape due to /dev/console mount and related races
    33Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-28642Mar 29, 2023 · AppArmor bypass with symlinked /proc in runc
    31Monitor
  • ← EarlierCVE-2024-45310Sep 3, 2024 · runc can be confused to create empty files/directories on the host
    14Monitor
  • Later →CVE-2025-52881Nov 6, 2025 · runc: LSM labels can be bypassed with malicious config using dummy procfs files
    29Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 kubernetes 1.30.10-14 on Azure Linux 3.01.30.10-15 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kubernetes 1.28.4-19 on CBL Mariner 2.01.28.4-20 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 moby-runc 1.1.9-9 on CBL Mariner 2.01.2.8-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:aardvark-dns2:1.10.1-2.module_el8.10.0+3909+6e1c1eb7 · AlmaLinux:8Package registry (OSV)
almalinux:buildah2:1.33.12-2.module_el8.10.0+4023+db236c53 · AlmaLinux:8Package registry (OSV)
almalinux:buildah-tests2:1.33.12-2.module_el8.10.0+4068+0e21408f · AlmaLinux:8Package registry (OSV)
almalinux:cockpit-podman84.1-1.module_el8.10.0+4016+efd18bf8 · AlmaLinux:8Package registry (OSV)
almalinux:conmon3:2.1.10-1.module_el8.10.0+3970+8445edf6 · AlmaLinux:8Package registry (OSV)
almalinux:container-selinux2:2.229.0-2.module_el8.10.0+3909+6e1c1eb7 · AlmaLinux:8Package registry (OSV)
almalinux:containernetworking-plugins1:1.4.0-6.module_el8.10.0+4016+efd18bf8 · AlmaLinux:8Package registry (OSV)
almalinux:containers-common2:1-82.module_el8.10.0+3876+e55593a8 · AlmaLinux:8Package registry (OSV)
almalinux:crit3.18-5.module_el8.10.0+3901+4b80ecd7 · AlmaLinux:8Package registry (OSV)
almalinux:criu3.18-5.module_el8.10.0+3926+f12484f5 · AlmaLinux:8Package registry (OSV)
almalinux:criu-devel3.18-5.module_el8.10.0+4016+efd18bf8 · AlmaLinux:8Package registry (OSV)
almalinux:runc4:1.2.5-3.el9_6 · AlmaLinux:9Package registry (OSV)
alpine:runc1.3.3-r0 · Alpine:v3.22Package registry (OSV)
debian:runc1.3.3+ds1-2 · Debian:14Package registry (OSV)
Go:github.com/opencontainers/runc1.2.8Package registry (OSV)
Go:github.com/opencontainers/runc1.3.3Package registry (OSV)
Go:github.com/opencontainers/runc1.4.0-rc.3Package registry (OSV)
opensuse:alloy1.12.2-2.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:buildah1.39.5-160000.1.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:podman4.9.5-150500.3.56.2 · openSUSE:Leap 15.6Package registry (OSV)
opensuse:runc1.2.7-150000.80.1 · openSUSE:Leap 15.6Package registry (OSV)
red hat:aardvark-dns2:1.10.1-2.module+el8.10.0+23647+cfd78660 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah2:1.33.12-2.module+el8.10.0+23647+cfd78660 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-debuginfo2:1.33.12-2.module+el8.10.0+23647+cfd78660 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-debugsource2:1.33.12-2.module+el8.10.0+23647+cfd78660 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-tests2:1.33.12-2.module+el8.10.0+23647+cfd78660 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:buildah-tests-debuginfo2:1.33.12-2.module+el8.10.0+23647+cfd78660 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)

+24

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:22025-11-12
Proof-of-concept repository on GitHubstars:22025-12-31
Proof-of-concept repository on GitHubstars:22026-01-18

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+5 d
  3. TodayNov 11, 2026+369 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-525650 days apartcontainer escape due to /dev/console mount and related races
    33Monitor
  • CVE-2025-528810 days apartrunc: LSM labels can be bypassed with malicious config using dummy procfs files
    29Monitor
  • CVE-2024-45310429 days apartrunc can be confused to create empty files/directories on the host
    14Monitor
  • CVE-2026-41579237 days apartrunc: Malicious image with /dev symlink can trigger limited host filesystem integrity violations
    13Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
A
Scope
X

Weakness class (CWE)

CWE-61 · UNIX Symbolic Link (Symlink) Following

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records