Apache Traffic Control - Router RegExp OOM Untrusted Input
CVE-2025-61581 Published on October 16, 2025
Apache Traffic Control: ReDoS issue in Traffic Router configuration
** UNSUPPORTED WHEN ASSIGNED ** Inefficient Regular Expression Complexity vulnerability in Apache Traffic Control.
This issue affects Apache Traffic Control: all versions.
People with access to the management interface of the Traffic Router component could specify malicious patterns and cause unavailability.
As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users.
NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
Vulnerability Analysis
CVE-2025-61581 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a ReDoS Vulnerability?
The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles. Some regular expression engines have a feature called "backtracking". If the token cannot match, the engine "backtracks" to a position that may result in a different token that can match. Backtracking becomes a weakness if all of these conditions are met:
CVE-2025-61581 has been classified to as a ReDoS vulnerability or weakness.
Products Associated with CVE-2025-61581
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Affected Versions
Apache Software Foundation Apache Traffic Control:- Before * is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.