CVE-2026-125063
Description
A flaw was found in the rrule validation of schedules in automation controller. Several non-anchored regular expressions with lazy wildcard prefixes are applied to the user-supplied rrule value; when the expected DTSTART/RRULE tokens are absent, validation time grows quadratically with the length of the value. An authenticated user can submit a large token-free rrule through the REST API, including the schedule preview endpoint, which requires no resource-level permissions; validation runs synchronously in the API web worker, so a single such request occupies a worker for an extended time and repeated requests can exhaust the web worker pool, denying access to the API and web UI while the attack is sustained. The impact is limited to availability.
Statement
This flaw affects the automation controller component of Red Hat Ansible Automation Platform. Exploitation requires an authenticated user, and any account is sufficient because the schedule preview endpoint does not require resource-level permissions. The impact is limited to denial of service of the controller web tier while the attack is sustained; there is no confidentiality or integrity impact, and service recovers once the malicious requests stop. Red Hat rates this Moderate. The recommended fix is to replace the non-anchored wildcard-prefixed regular expressions in the rrule validation with anchored patterns or explicit token searches, to parse the submitted value once instead of rescanning it for each check, and to cap the accepted rrule length at the serializer field before validation runs.
Mitigation
The schedule preview endpoint is available to any authenticated user and cannot be restricted by RBAC, so exposure can only be reduced by limiting API access to trusted users.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | Low | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Red Hat CVSS v3 Score Explanation
A:L per harakiri-bounded per-request impact and immediate recovery; A:H alternative (6.5) documented in triage. See PSIRTSUPT-29874 analysis.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Attackers can create crafted inputs that intentionally cause the regular expression to use excessive backtracking in a way that causes the CPU consumption to spike.
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