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.

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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.

History

Thu, 12 Nov 2026 11:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Ansible.posix: authorized_key module follows a parent-directory symlink allowing writes outside the intended directory
First Time appeared Redhat
Redhat enterprise Linux
Weaknesses CWE-59
CPEs cpe:/a:redhat:enterprise_linux:10
cpe:/a:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
References
Metrics cvssV3_1

{'score': 3.9, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-11-12T10:50:16.148Z

Reserved: 2026-11-11T10:46:47.355Z

Link: CVE-2026-126644

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-11-12T11:17:11.770

Modified: 2026-11-12T11:17:11.920

Link: CVE-2026-126644

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses