# CVE-2026-126644: Ansible.posix: authorized_key module follows a parent-directory symlink allowing writes outside the intended directory

Status: published. Published: 2026-11-12. Updated: 2026-11-12.

A link-following flaw was found in the authorized_key module of the ansible.posix collection, residual to the fix for CVE-2026-11837. That fix guards only the final path component (os.chown with follow_symlinks=False and O_NOFOLLOW in _safe_open_write()). When an unprivileged local user replaces their ~/.ssh directory with a symlink to a directory they do not own, and an operator subsequently runs the authorized_key task as root (a common provisioning pattern), the module resolves its path operations through the symlink: atomic_move() writes the temporary file in the symlink target and renames it to <target>/authorized_keys, creating or overwriting a file in the attacker-chosen directory, and os.chmod(sshdir, 0o700) follows the symlink and changes the target directory's permissions. The written file is chowned to the unprivileged user, so this is not a privilege escalation, but it allows an attacker to create or overwrite files (for example in /etc/apt/apt.conf.d/, which APT reads regardless of file ownership) to cause integrity and availability impacts.

## Remediation

- workaround: Do not run ansible.posix.authorized_key as root against home or .ssh directories that unprivileged users can modify. Verify that target directories are not attacker-controllable symlinks before running the task. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (rhc-worker-playbook): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (rhc-worker-playbook): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 3.9 (low); CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L; source: CNA: redhat

- CVSS 3.1: 3.9 (low); CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-59

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-126644 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2571732 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-126644 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2571732 (secalert@redhat.com)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-126644; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126644; retrieved 2026-11-12; source updated 2026-11-12

Revision: ecd05be0a14b264184a3d448c49c940ea50b10969c3e09cba8952d5e7e085486

Canonical: https://y2.dev/cve/CVE-2026-126644

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