apache-opennlp — security advisory
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
- Products
- apache-opennlp
- Affected versions
- 1.9.1-2, 1.9.2-1, 1.9.3-1, 1.9.4-1, 2.3.0-1, 2.3.1-1, 2.3.1-2, 2.3.2-1, 2.5.3-1, 2.5.3-1build1, 2.5.9-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-82617
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:20 UTC · Revision 1
Source evidence
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
osv:UBUNTU-CVE-2026-82617
apache-opennlp
Fixed versions: Not specified
apache-opennlp
Fixed versions: Not specified
apache-opennlp
Fixed versions: Not specified
apache-opennlp
Fixed versions: Not specified
apache-opennlp
Fixed versions: Not specified
Complete source record
{
"id": "2fd472a1dff544ff10b13b7919faefd76fdea3bf889e78413a2a074f1f8d87a1",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-82617",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-82617",
"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 ",
"evidence": "osv:UBUNTU-CVE-2026-82617",
"products": [
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"affected_versions": [
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"evidence": "/affected/3/versions"
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],
"severity": "critical",
"structured": {
"id": "UBUNTU-CVE-2026-82617",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V4",
"score": "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"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
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],
"affected": [
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],
"package": {
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"purl": "pkg:deb/ubuntu/apache-opennlp?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"1.9.1-2",
"1.9.2-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-82617.json"
},
"ecosystem_specific": {
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"ecosystem": "Ubuntu:22.04:LTS"
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"database_specific": {
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{
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"ecosystem": "Ubuntu:24.04:LTS"
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],
"modified": "2026-10-17T13:01:11.331208950Z",
"provider": "osv",
"upstream": [
"CVE-2026-82617"
],
"references": [
"https://ubuntu.com/security/CVE-2026-82617",
"https://www.cve.org/CVERecord?id=CVE-2026-82617",
"https://lists.apache.org/thread/spzhcxxszqdpppg70m1zz2l3mv29mhl3"
]
},
"related_cves": [
{
"value": "CVE-2026-82617",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 361173,
"published_at": "2026-09-11T18:16:00+00:00"
}