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Fencer Vulns
high 7.8

CVE-2025-31133 json

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

published 2025-11-05 12 mo ago modified 2026-10-07 32 d ago also EUVD-2025-37945 , GHSA-9493-h29p-rfm2 , GO-2025-4096

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/opencontainers/runc 1.2.8, 1.3.3, 1.4.0-rc.3
  • linuxfoundation runc 1.2.8, 1.3.3
  • runc Debian 14 1.3.3+ds1-2

debian advisories DEBIAN-CVE-2025-31133

  • runc-app Ubuntu 22.04 LTS 1.3.3-0ubuntu1~22.04.2
  • runc-app Ubuntu 24.04 LTS 1.3.3-0ubuntu1~24.04.2
  • runc-app Ubuntu 25.10 1.3.3-0ubuntu1~25.10.2
  • runc-stable Ubuntu 25.10 1.3.3-0ubuntu1~25.10.2

ubuntu advisories UBUNTU-CVE-2025-31133

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • runc openshift 4.17, openshift 4.14 4:1.2.5-2.rhaos4.17.el8
  • runc openshift 4.17, openshift 4.14 4:1.2.5-2.rhaos4.17.el9
  • perf openshift 4.15 5.14.0-284.155.1.el9_2
  • rtla openshift 4.15 5.14.0-284.155.1.el9_2
  • runc openshift 4.16, openshift 4.15, openshift 4.14 +1 more 4:1.2.9-1.rhaos4.16.el8
  • runc openshift 4.16, openshift 4.15, openshift 4.14 +1 more 4:1.2.9-1.rhaos4.16.el9
  • kernel openshift 4.15 5.14.0-284.155.1.el9_2
  • bpftool openshift 4.15 7.0.0-284.155.1.el9_2

red hat advisories RHBA-2025:21221RHSA-2026:1540RHSA-2026:10703RHSA-2026:8325RHSA-2026:4693RHSA-2026:4531

  • runc SLE Module for Basesystem 15 SP7, SLE Micro 5.5, SLE Micro 5.4 +2 more 1.3.6-150000.101.1
  • runc SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 1.3.6-160000.1.1
  • podman SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 5.4.2-160000.4.1
  • alloy SLES for SAP applications 16.0, SLES 16.0 1.12.2-160000.1.1
  • alloy SLE Module for Basesystem 15 SP7 1.12.2-150700.15.15.1
  • buildah SLES for SAP applications 16.0, SLES 16.0 1.39.5-160000.1.1
  • podman SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 5.4.2-160000.3.1
  • runc SLE Module for Containers 15 SP6, SLE Module for Basesystem 15 SP7, SLE Micro 5.5 +16 more 1.3.3-150000.85.1

suse advisories SUSE-SU-2026:3433-1SUSE-SU-2026:3428-1SUSE-SU-2026:22938-1SUSE-SU-2026:22942-1SUSE-SU-2026:20626-1SUSE-SU-2026:20641-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • runc openSUSE Leap 16.0 1.3.6-160000.1.1
  • podman openSUSE Leap 16.0 5.4.2-160000.4.1
  • alloy openSUSE Leap 16.0 1.12.2-160000.1.1
  • buildah openSUSE Leap 16.0 1.39.5-160000.1.1
  • podman openSUSE Leap 16.0 5.4.2-160000.3.1
  • alloy openSUSE Tumbleweed 1.12.2-2.1
  • runc openSUSE Leap 16.0 1.3.3-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:21431-1openSUSE-SU-2026:20305-1openSUSE-SU-2026:20140-1openSUSE-SU-2026:20080-1openSUSE-SU-2026:20072-1

  • crit AlmaLinux 8 3.18-5.module_el8.10.0+3901+4b80ecd7
  • crit AlmaLinux 8 3.18-5.module_el8.10.0+4068+0e21408f
  • crit AlmaLinux 8 3.18-5.module_el8.10.0+3845+87b84552
  • crit AlmaLinux 8 3.18-5.module_el8.10.0+3858+6ad51f9f
  • criu AlmaLinux 8 3.18-5.module_el8.10.0+3926+f12484f5
  • criu AlmaLinux 8 3.18-5.module_el8.10.0+3876+e55593a8
  • criu AlmaLinux 8 3.18-5.module_el8.10.0+3970+8445edf6
  • criu AlmaLinux 8 3.18-5.module_el8.10.0+3909+6e1c1eb7

almalinux advisories ALSA-2025:21232ALSA-2025:20957ALSA-2025:19927

  • criu Rocky Linux 8 3.18-5.module+el8.10.0+2001+6a33db9f
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1880+8e896d1b
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1843+6892ab28
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1948+4b5cd4a9
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1874+ce489889
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1825+623b0c20
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1896+b18fa106
  • criu Rocky Linux 8 3.18-5.module+el8.10.0+1815+5fe7415e

rocky linux advisories RLSA-2025:21232RLSA-2025:20957

  • runc Alpine 3.24, Alpine 3.23, Alpine 3.22 1.3.3-r0

alpine advisories ALPINE-CVE-2025-31133

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • moby-runc CBL-Mariner 2.0 1.2.8-1
  • kubernetes CBL-Mariner 2.0 1.28.4-21
  • kubernetes Azure Linux 3.0 1.30.10-16

azure linux advisories AZL-69818AZL-70547AZL-70592

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-31133 updated cvss 8.2

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

  • Red Hat Enterprise Linux AppStream (v. 8) crit 3.18-5.module+el8.10.0+23647+cfd78660, criu 3.18-5.module+el8.10.0+23647+cfd78660, runc 1.2.5-2.module+el8.10.0+23647+cfd78660, crun 1.14.3-2.module+el8.10.0+23647+cfd78660, udica 0.2.6-21.module+el8.10.0+23647+cfd78660, conmon 2.1.10-1.module+el8.10.0+23647+cfd78660, +27 more
    fixed: vendor fix RHSA-2025:21232
  • Red Hat Enterprise Linux AppStream (v. 9) runc 1.2.5-3.el9_6, runc 1.3.0-4.el9_7
    fixed: vendor fix RHSA-2025:19927
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) crit 3.15-3.module+el8.6.0+24209+25a14987, criu 3.15-3.module+el8.6.0+24209+25a14987, crun 1.14.3-1.module+el8.6.0+24209+25a14987, udica 0.2.6-5.module+el8.6.0+24209+25a14987, conmon 2.1.4-1.module+el8.6.0+24209+25a14987, runc 1.2.9-1.module+el8.6.0+24209+25a14987.1, +27 more Red Hat Enterprise Linux AppStream E4S (v.8.6) crit 3.15-3.module+el8.6.0+24209+25a14987, criu 3.15-3.module+el8.6.0+24209+25a14987, crun 1.14.3-1.module+el8.6.0+24209+25a14987, udica 0.2.6-5.module+el8.6.0+24209+25a14987, conmon 2.1.4-1.module+el8.6.0+24209+25a14987, runc 1.2.9-1.module+el8.6.0+24209+25a14987.1, +27 more
    fixed: vendor fix RHSA-2026:10703
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) crit 3.15-4.module+el8.8.0+23884+2031fc78, criu 3.15-4.module+el8.8.0+23884+2031fc78, runc 1.2.9-1.module+el8.8.0+23884+2031fc78, crun 1.14.3-1.module+el8.8.0+23884+2031fc78, conmon 2.1.6-1.module+el8.8.0+23884+2031fc78, udica 0.2.6-20.module+el8.8.0+23884+2031fc78, +27 more
    fixed: vendor fix RHSA-2026:4693
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) runc 1.2.9-1.el9_0
    fixed: vendor fix RHSA-2026:8325
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) runc 1.2.9-1.el9_2.1
    fixed: vendor fix RHSA-2026:4531
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) runc 1.2.9-1.el9_4
    fixed: vendor fix RHSA-2026:0425
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) crit 3.15-3.module+el8.6.0+24209+25a14987, criu 3.15-3.module+el8.6.0+24209+25a14987, crun 1.14.3-1.module+el8.6.0+24209+25a14987, udica 0.2.6-5.module+el8.6.0+24209+25a14987, conmon 2.1.4-1.module+el8.6.0+24209+25a14987, runc 1.2.9-1.module+el8.6.0+24209+25a14987.1, +27 more
    fixed: vendor fix RHSA-2026:10703
show 12 more
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) crit 3.15-4.module+el8.8.0+23884+2031fc78, criu 3.15-4.module+el8.8.0+23884+2031fc78, runc 1.2.9-1.module+el8.8.0+23884+2031fc78, crun 1.14.3-1.module+el8.8.0+23884+2031fc78, conmon 2.1.6-1.module+el8.8.0+23884+2031fc78, udica 0.2.6-20.module+el8.8.0+23884+2031fc78, +27 more
    fixed: vendor fix RHSA-2026:4693
  • Red Hat OpenShift Container Platform 4.12 rhcos 412.86.202604010116, runc 1.2.9-1.rhaos4.17.el8
    fixed: vendor fix RHSA-2026:6492
  • Red Hat OpenShift Container Platform 4.13 rhcos 413.92.202511261311, runc 1.2.9-1.rhaos4.16.el8, runc 1.2.9-1.rhaos4.16.el9
    fixed: vendor fix RHSA-2026:0676
  • Red Hat OpenShift Container Platform 4.14 runc 1.2.5-2.rhaos4.17.el8, runc 1.2.5-2.rhaos4.17.el9, runc 1.2.9-1.rhaos4.16.el8, runc 1.2.9-1.rhaos4.16.el9
    fixed: vendor fix RHSA-2025:21328
  • Red Hat OpenShift Container Platform 4.15 rhcos 415.92.202512100122, runc 1.2.9-1.rhaos4.16.el8, runc 1.2.9-1.rhaos4.16.el9
    fixed: vendor fix RHSA-2026:1540
  • Red Hat OpenShift Container Platform 4.16 rhcos 416.94.202511191934, runc 1.2.9-1.rhaos4.16.el8, runc 1.2.9-1.rhaos4.16.el9
    fixed: vendor fix RHSA-2026:0418
  • Red Hat OpenShift Container Platform 4.17 runc 1.2.5-2.rhaos4.17.el8, runc 1.2.5-2.rhaos4.17.el9, runc 1.2.9-1.rhaos4.17.el9
    fixed: vendor fix RHBA-2025:21221
  • Red Hat OpenShift Container Platform 4.18 rhcos 418.94.202511170715, runc 1.2.9-1.rhaos4.18.el8, runc 1.2.9-1.rhaos4.18.el9
    fixed: vendor fix RHSA-2026:0331
  • Red Hat OpenShift Container Platform 4.19 runc 1.2.5-2.rhaos4.19.el9
    fixed: vendor fix RHBA-2025:21361
  • Red Hat OpenShift Container Platform 4.20 rhcos 4.20.9.6.202511102206
    fixed: vendor fix RHBA-2025:21224
  • Red Hat Quay 3.16 quay 1770816438
    fixed: vendor fix RHSA-2026:2681
  • Red Hat Ironic content for Red Hat OpenShift Container Platform 4.15 python-eventlet 0.33.1-7.el9, python3-eventlet 0.33.1-7.el9 Red Hat Enterprise Linux AppStream E4S (v.9.0) crun 1.14.3-1.el9_0, podman 4.2.0-6.el9_0.6, buildah 1.26.9-1.el9_0.3, skopeo 1.8.0-4.1.el9_0.2, podman-tests 4.2.0-6.el9_0.6, podman-docker 4.2.0-6.el9_0.6, +6 more Red Hat OpenShift Container Platform 4 openshift-clients, openshift-clients-redistributable Red Hat OpenShift Container Platform 4.12 perf 4.18.0-372.175.1.el8_6, kernel 4.18.0-372.175.1.el8_6, bpftool 4.18.0-372.175.1.el8_6, kernel-core 4.18.0-372.175.1.el8_6, kernel-tools 4.18.0-372.175.1.el8_6, python3-perf 4.18.0-372.175.1.el8_6, +20 more Red Hat OpenShift Container Platform 4.13 perf 5.14.0-284.153.1.el9_2, rtla 5.14.0-284.153.1.el9_2, bpftool 7.0.0-284.153.1.el9_2, kernel 5.14.0-284.153.1.el9_2, kernel-64k 5.14.0-284.153.1.el9_2, kernel-core 5.14.0-284.153.1.el9_2, +66 more Red Hat OpenShift Container Platform 4.14 cri-tools 1.27.0-7.el8, cri-tools 1.27.0-7.el9, perf 5.14.0-284.147.1.el9_2, perf 5.14.0-284.154.1.el9_2, rtla 5.14.0-284.147.1.el9_2, rtla 5.14.0-284.154.1.el9_2, +147 more
    +6 more products
    Red Hat OpenShift Container Platform 4.15 perf 5.14.0-284.155.1.el9_2, rtla 5.14.0-284.155.1.el9_2, bpftool 7.0.0-284.155.1.el9_2, kernel 5.14.0-284.155.1.el9_2, kernel-64k 5.14.0-284.155.1.el9_2, kernel-core 5.14.0-284.155.1.el9_2, +66 more Red Hat OpenShift Container Platform 4.16 rv 5.14.0-427.105.1.el9_4, perf 5.14.0-427.105.1.el9_4, rtla 5.14.0-427.105.1.el9_4, bpftool 7.3.0-427.105.1.el9_4, kernel 5.14.0-427.105.1.el9_4, podman 4.9.4-19.rhaos4.16.el8, +80 more Red Hat OpenShift Container Platform 4.17 perf 5.14.0-427.106.1.el9_4, perf 5.14.0-427.107.1.el9_4, rtla 5.14.0-427.106.1.el9_4, rtla 5.14.0-427.107.1.el9_4, bpftool 7.3.0-427.106.1.el9_4, bpftool 7.3.0-427.107.1.el9_4, +146 more Red Hat OpenShift Container Platform 4.18 perf 5.14.0-427.105.1.el9_4, rtla 5.14.0-427.105.1.el9_4, podman 5.2.2-6.rhaos4.18.el8, bpftool 7.3.0-427.105.1.el9_4, kernel 5.14.0-427.105.1.el9_4, podman 5.2.2-14.rhaos4.18.el9, +80 more Red Hat OpenShift Container Platform 4.19 ignition 2.21.0-5.el9_6, rv 5.14.0-570.64.1.el9_6, perf 5.14.0-570.64.1.el9_6, rtla 5.14.0-570.64.1.el9_6, kernel 5.14.0-570.64.1.el9_6, libperf 5.14.0-570.64.1.el9_6, +96 more Red Hat Quay 3.16 quay 1770230686, quay 1770762347, quay 1770816239, quay 1770816381, quay 1770816399, quay 1770816415, +3 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
12 mo ago

Exploit prediction

1.24% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.3 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
CNA 4.0 7.3 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 3.1 7.8 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/opencontainers/runc
<1.2.8
>=1.3.0-rc.1, <1.3.3
>=1.4.0-rc.1, <1.4.0-rc.3
1.2.8
1.3.3
1.4.0-rc.3

Affected products

  • opencontainers runc

Classification

Weakness
  • CWE-61 UNIX Symbolic Link (Symlink) Following
  • CWE-363 Race Condition Enabling Link Following

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.