Ansible.posix: authorized_key module follows a parent-directory symlink allowing writes outside the intended directory
Summary
| CVE | CVE-2026-126644 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-12 11:17:11 UTC |
| Updated | 2026-11-12 11:17:11 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 3.9 LOW from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L
Problem Types: CWE-59 | CWE-59 Improper Link Resolution Before File Access
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 3.9 | LOW | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L |
| 3.1 | CNA | CVSS | 3.9 | LOW | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
RequiredScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
LowCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| CNA | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-126644 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-11-11T14:31:37.694Z | Reported to Red Hat. |
| CNA | 2026-11-11T14:33:28.109Z | Made public. |
Workarounds
CNA: 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.
There are currently no legacy QID mappings associated with this CVE.