---
title: "CVE-2026-82617: Apache OpenNLP - Denial of Service"
description: "Apache OpenNLP 2.0.0 through 2.5.11 and 3.0.0-M1 through 3.0.0-M5 contain a denial of service caused by ambiguous nested quantifiers in built-in RegexNameFinder patterns for EMAIL and URL, letting attackers supply crafted text to cause excessive CPU usage or thread crashes, exploit requires attacker to supply untrusted text for analysis."
url: https://panop.io/threat-heartbeat/CVE-2026-82617/
---

# CVE-2026-82617 Apache OpenNLP - Denial of Service

Apache OpenNLP 2.0.0 through 2.5.11 and 3.0.0-M1 through 3.0.0-M5 contain a denial of service caused by ambiguous nested quantifiers in built-in RegexNameFinder patterns for EMAIL and URL, letting attackers supply crafted text to cause excessive CPU usage or thread crashes, exploit requires attacker to supply untrusted text for analysis.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.77% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-82617)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

11 September 2026

Updated

15 October 2026

Weakness

[CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)

## Vendor fix

Upgrade to version 2.5.12 or 3.0.0-M6.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-82617](https://nvd.nist.gov/vuln/detail/CVE-2026-82617)
- [http://www.openwall.com/lists/oss-security/2026/09/11/10](http://www.openwall.com/lists/oss-security/2026/09/11/10)
- [https://lists.apache.org/thread/spzhcxxszqdpppg70m1zz2l3mv29mhl3](https://lists.apache.org/thread/spzhcxxszqdpppg70m1zz2l3mv29mhl3)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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