Denial of service via built-in name-finder regexes
Published Sep 11, 2026 · Updated Sep 11, 2026
Denial of service in Apache OpenNLP 2.0.0 through 2.5.11 and 3.0.0-M1 through 3.0.0-M5 allows attackers to hang or kill a thread. RegexNameFinder.find passes concatenated text to built-in EMAIL and URL patterns whose ambiguous repetitions cause quadratic rescanning or unbounded matcher recursion. Reachability requires an embedding application to select either finder and analyze attacker-controlled text; no authentication, model file, or special configuration is required.
Summary
What happened
Denial of service in Apache OpenNLP 2.0.0 through 2.5.11 and 3.0.0-M1 through 3.0.0-M5 allows attackers to hang or kill a thread. RegexNameFinder.find passes concatenated text to built-in EMAIL and URL patterns whose ambiguous repetitions cause quadratic rescanning or unbounded matcher recursion. Reachability requires an embedding application to select either finder and analyze attacker-controlled text; no authentication, model file, or special configuration is required.
The record
- CVE
- CVE-2026-82617
- Published
- Sep 11, 2026
- Updated
- Sep 11, 2026
- Vendor
- The Apache Software Foundation
- Product
- Apache OpenNLP
- Classifications
- CWE-400, CWE-674, CWE-1333, T1499.002
- Attack vector
- Unavailable
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 11, 2026CVE publishedPublication date reported by the CVE source.
- Sep 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.0.0 <2.5.12
- Affected versionversion=3.0.0-M1 <3.0.0-M6
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Apache OpenNLP RegexNameFinderFactory regression testproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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