CVE-2026-41579

Host filesystem modification via symlinked container device directory

Published Jul 1, 2026 · Updated Jul 1, 2026

Symlink following in runc before 1.3.6, 1.4.0 through 1.4.2 and 1.5.0-rc.1 through 1.5.0-rc.2 allows attackers to modify Linux host files. During rootfs setup, setupPtmx and setupDevSymlinks pass joined paths to os.Remove and os.Symlink without confining a symlinked /dev beneath the container root, enabling deletion of host files named ptmx or creation of six fixed symlinks in an existing host directory. Exploitation requires a higher-level runtime to process the crafted image; Docker masks the image's top-level /dev, while Podman remains exposed and user namespaces or LSM policy can constrain writable host locations.

CVSS severity3.3
Low
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Symlink following in runc before 1.3.6, 1.4.0 through 1.4.2 and 1.5.0-rc.1 through 1.5.0-rc.2 allows attackers to modify Linux host files. During rootfs setup, setupPtmx and setupDevSymlinks pass joined paths to os.Remove and os.Symlink without confining a symlinked /dev beneath the container root, enabling deletion of host files named ptmx or creation of six fixed symlinks in an existing host directory. Exploitation requires a higher-level runtime to process the crafted image; Docker masks the image's top-level /dev, while Podman remains exposed and user namespaces or LSM policy can constrain writable host locations.

The record

CVE
CVE-2026-41579
Published
Jul 1, 2026
Updated
Jul 1, 2026
Vendor
Open Container Initiative
Product
runc
Classifications
CWE-61, T1611
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.3.6
  2. Affected versionversion=>= 1.4.0-rc.1, < 1.4.3
  3. Affected versionversion=>= 1.5.0-rc.1, < 1.5.0-rc.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Open Container Initiative · runcversion=< 1.3.6; version=>= 1.4.0-rc.1, < 1.4.3; version=>= 1.5.0-rc.1, < 1.5.0-rc.3

Published CVSS scores

3.3GitHub Security AdvisoryCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-61UNIX Symbolic Link (Symlink) Following
T1611Escape to Host

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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