FKIE_CVE-2026-82617
Vulnerability from fkie_nvd - Published: 2026-09-11 18:16 - Updated: 2026-09-11 21:17
Severity
Summary
The two built-in name-finder patterns exposed by
opennlp.tools.namefind.RegexNameFinderFactory - DEFAULT_REGEX_NAME_FINDER.EMAIL
and DEFAULT_REGEX_NAME_FINDER.URL - contain ambiguous nested quantifiers. An
application that obtains these finders through
RegexNameFinderFactory.getDefaultRegexNameFinders(...) and then applies them to
untrusted text through RegexNameFinder.find(String[]) or RegexNameFinder.find(String)
can be driven into super-linear backtracking or into unbounded matcher recursion by a
small crafted input.
For the EMAIL pattern, a long run of local-part characters that is never followed by an
@ forces the matcher to re-scan to end-of-input from every starting offset. Cost grows
quadratically with input length: an input of approximately 32 KB consumes several seconds
of CPU in a single find() call and returns no match, and each doubling of the input
multiplies the cost roughly four-fold.
For the URL pattern, the query-string sub-expression nests a capturing repetition inside
an outer repetition. The JDK matcher recurses once per query token, so an input of
approximately 4 KB containing many &-separated tokens exhausts the thread stack and
causes java.lang.StackOverflowError to propagate out of find(), terminating the
calling thread. On a thread created with a smaller stack (for example -Xss512k, typical
of server worker pools) approximately 1 KB is sufficient.
In both cases an attacker who can supply text for analysis can convert a single request
into seconds to minutes of pinned CPU, or into an abrupt thread death, denying service to
the embedding application. No authentication, special configuration, or model file is
required beyond the application having selected one of the two built-in finders.
This issue affects Apache OpenNLP: from 2.0.0 through 2.5.11; from 3.0.0-M1 through
3.0.0-M5.
Users are recommended to upgrade to version 2.5.12, or to 3.0.0-M6 for users tracking the
3.0.0 milestone line, which fix the issue.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://repo.maven.apache.org/maven2",
"defaultStatus": "unaffected",
"packageName": "org.apache.opennlp:opennlp-core",
"packageURL": "pkg:maven/org.apache.opennlp/opennlp-core",
"product": "Apache OpenNLP",
"vendor": "Apache Software Foundation",
"versions": [
{
"lessThan": "3.0.0-M6",
"status": "affected",
"version": "3.0.0-M1",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://repo.maven.apache.org/maven2",
"defaultStatus": "unaffected",
"packageName": "org.apache.opennlp:opennlp-tools",
"packageURL": "pkg:maven/org.apache.opennlp/opennlp-tools",
"product": "Apache OpenNLP",
"vendor": "Apache Software Foundation",
"versions": [
{
"lessThan": "2.5.12",
"status": "affected",
"version": "2.0.0",
"versionType": "semver"
}
]
}
],
"source": "security@apache.org"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "The two built-in name-finder patterns exposed by\nopennlp.tools.namefind.RegexNameFinderFactory - DEFAULT_REGEX_NAME_FINDER.EMAIL\nand DEFAULT_REGEX_NAME_FINDER.URL\u00a0- contain ambiguous nested quantifiers. An\napplication that obtains these finders through\nRegexNameFinderFactory.getDefaultRegexNameFinders(...) and then applies them to\nuntrusted text through RegexNameFinder.find(String[]) or RegexNameFinder.find(String)\ncan be driven into super-linear backtracking or into unbounded matcher recursion by a\nsmall crafted input.\n\n\n\n\n\nFor the EMAIL pattern, a long run of local-part characters that is never followed by an\n@ forces the matcher to re-scan to end-of-input from every starting offset. Cost grows\nquadratically with input length: an input of approximately 32 KB consumes several seconds\nof CPU in a single find() call and returns no match, and each doubling of the input\nmultiplies the cost roughly four-fold.\n\n\n\n\n\nFor the URL pattern, the query-string sub-expression nests a capturing repetition inside\nan outer repetition. The JDK matcher recurses once per query token, so an input of\napproximately 4 KB containing many \u0026-separated tokens exhausts the thread stack and\ncauses java.lang.StackOverflowError to propagate out of find(), terminating the\ncalling thread. On a thread created with a smaller stack (for example -Xss512k, typical\nof server worker pools) approximately 1 KB is sufficient.\n\n\n\n\n\nIn both cases an attacker who can supply text for analysis can convert a single request\ninto seconds to minutes of pinned CPU, or into an abrupt thread death, denying service to\nthe embedding application. No authentication, special configuration, or model file is\nrequired beyond the application having selected one of the two built-in finders.\n\n\n\n\n\nThis issue affects Apache OpenNLP: from 2.0.0 through 2.5.11; from 3.0.0-M1 through\n3.0.0-M5.\n\n\n\n\n\n\n\n\n\nUsers are recommended to upgrade to version 2.5.12, or to 3.0.0-M6 for users tracking the\n3.0.0 milestone line, which fix the issue."
}
],
"id": "CVE-2026-82617",
"lastModified": "2026-09-11T21:17:25.553",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 10.0,
"baseSeverity": "CRITICAL",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "HIGH",
"subConfidentialityImpact": "HIGH",
"subIntegrityImpact": "HIGH",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"source": "security@apache.org",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-82617",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-11T17:57:46.105698Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-11T18:16:59.443",
"references": [
{
"source": "security@apache.org",
"url": "https://lists.apache.org/thread/spzhcxxszqdpppg70m1zz2l3mv29mhl3"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "http://www.openwall.com/lists/oss-security/2026/09/11/10"
}
],
"sourceIdentifier": "security@apache.org",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-1333"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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