CVE-2026-82617: Apache OpenNLP · ReDoS
Affects Apache OpenNLPSource CVE Database V5
Not known to be exploited · CVSS 10.0 Critical : upgrade to 3.0.0-M6 as a priority.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 55% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.0.0-M6, 2.5.12
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Apache to 3.0.0-M6 (OpenNLP, Software Foundation/org.apache.opennlp:opennlp-core) or 2.5.12 (OpenNLP, Software Foundation/org.apache.opennlp:opennlp-tools).
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Apache Software FoundationApache OpenNLP | Affected
| Fixed in
|
| Apache Software FoundationApache OpenNLP | Affected
| Fixed in
|
MavenApache Software Foundation/org.apache.opennlp:opennlp-corepkg:maven/Apache Software Foundation/org.apache.opennlp:opennlp-coreOther threats | Affected
| Fixed in
|
MavenApache Software Foundation/org.apache.opennlp:opennlp-toolspkg:maven/Apache Software Foundation/org.apache.opennlp:opennlp-toolsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should upgrade Apache OpenNLP to version 2.5.12 or later, or to 3.0.0-M6 or later if using the 3.0.0 milestone line. These versions contain fixes that eliminate the ambiguous nested quantifiers causing the vulnerability. No other mitigation is required once upgraded.
Description
CVE-2026-82617 is a critical vulnerability in Apache OpenNLP affecting versions from 2.0.0 through 2.5.11 and 3.0.0-M1 through 3.0.0-M5. It involves two built-in name-finder regex patterns for EMAIL and URL that contain ambiguous nested quantifiers. These patterns can cause super-linear backtracking or unbounded recursion when processing crafted inputs, leading to high CPU usage or thread crashes. The vulnerability allows denial of service without requiring authentication or special configuration. Fixed versions 2.5.12 and 3.0.0-M6 address this issue.