Vulnerability-Lookup

ubuntu-cve-2026-82617

Vulnerability from osv_ubuntu

Published

2026-09-11 18:16

Modified

2026-09-16 11:43

Summary

Details

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.

Severity

10.0 (Critical)


                    
                      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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-82617	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-82617	REPORT
	https://lists.apache.org/thread/spzhcxxszqdpppg70…	REPORT
	http://www.openwall.com/lists/oss-security/2026/0…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libapache-opennlp-java",
            "binary_version": "1.9.2-1"
          },
          {
            "binary_name": "opennlp",
            "binary_version": "1.9.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "apache-opennlp",
        "purl": "pkg:deb/ubuntu/apache-opennlp@1.9.2-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.9.1-2",
        "1.9.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libapache-opennlp-java",
            "binary_version": "1.9.4-1"
          },
          {
            "binary_name": "opennlp",
            "binary_version": "1.9.4-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "apache-opennlp",
        "purl": "pkg:deb/ubuntu/apache-opennlp@1.9.4-1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.9.3-1",
        "1.9.4-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libapache-opennlp-java",
            "binary_version": "2.3.2-1"
          },
          {
            "binary_name": "opennlp",
            "binary_version": "2.3.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "apache-opennlp",
        "purl": "pkg:deb/ubuntu/apache-opennlp@2.3.2-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.3.0-1",
        "2.3.1-1",
        "2.3.1-2",
        "2.3.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libapache-opennlp-java",
            "binary_version": "2.5.3-1build1"
          },
          {
            "binary_name": "opennlp",
            "binary_version": "2.5.3-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "apache-opennlp",
        "purl": "pkg:deb/ubuntu/apache-opennlp@2.5.3-1build1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.5.3-1",
        "2.5.3-1build1"
      ]
    }
  ],
  "aliases": [],
  "details": "The two built-in name-finder patterns exposed by opennlp.tools.namefind.RegexNameFinderFactory - DEFAULT_REGEX_NAME_FINDER.EMAIL and DEFAULT_REGEX_NAME_FINDER.URL\u00a0- 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 \u0026-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.",
  "id": "UBUNTU-CVE-2026-82617",
  "modified": "2026-09-16T11:43:09Z",
  "published": "2026-09-11T18:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-82617"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-82617"
    },
    {
      "type": "REPORT",
      "url": "https://lists.apache.org/thread/spzhcxxszqdpppg70m1zz2l3mv29mhl3"
    },
    {
      "type": "REPORT",
      "url": "http://www.openwall.com/lists/oss-security/2026/09/11/10"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "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_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-82617"
  ]
}

CVE-2026-82617 (GCVE-0-2026-82617)

Vulnerability from cvelistv5 – Published: 2026-09-11 17:50 – Updated: 2026-09-11 21:07

Title

Apache OpenNLP, Apache OpenNLP: ReDoS / stack exhaustion in RegexNameFinderFactory built-in EMAIL and URL patterns

Summary

Severity

10 (Critical)


                        
                          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

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-11 17:57 UTC

CWE

CWE-1333 - Inefficient Regular Expression Complexity

Assigner

apache mitre root

References

2 references

URL	Tags
https://lists.apache.org/thread/spzhcxxszqdpppg70…	vendor-advisory
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

2 products

Vendor	Product	Version
Apache Software Foundation	Apache OpenNLP	Affected: 3.0.0-M1 , < 3.0.0-M6 (semver)
Apache Software Foundation	Apache OpenNLP	Affected: 2.0.0 , < 2.5.12 (semver)

Credits

n0mi1k

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-82617",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-11T17:57:46.105698Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-1333",
                "description": "CWE-1333 Inefficient Regular Expression Complexity",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-11T17:57:49.583Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-09-11T21:07:10.400Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/09/11/10"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "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"
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          ]
        },
        {
          "collectionURL": "https://repo.maven.apache.org/maven2",
          "defaultStatus": "unaffected",
          "packageName": "org.apache.opennlp:opennlp-tools",
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        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "n0mi1k"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
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              "type": "text/html",
              "value": "\u003cp\u003e\u003cspan\u003eThe two built-in name-finder patterns exposed by\n\u003c/span\u003e\u003ccode\u003eopennlp.tools.namefind.RegexNameFinderFactory\u003c/code\u003e\u003cspan\u003e - \u003c/span\u003e\u003ccode\u003eDEFAULT_REGEX_NAME_FINDER.EMAIL\u003c/code\u003e\u003cspan\u003e\nand \u003c/span\u003e\u003ccode\u003eDEFAULT_REGEX_NAME_FINDER.URL\u003c/code\u003e\u003cspan\u003e\u0026nbsp;- contain ambiguous nested quantifiers. An\napplication that obtains these finders through\n\u003c/span\u003e\u003ccode\u003eRegexNameFinderFactory.getDefaultRegexNameFinders(...)\u003c/code\u003e\u003cspan\u003e and then applies them to\nuntrusted text through \u003c/span\u003e\u003ccode\u003eRegexNameFinder.find(String[])\u003c/code\u003e\u003cspan\u003e or \u003c/span\u003e\u003ccode\u003eRegexNameFinder.find(String)\u003c/code\u003e\u003cspan\u003e\ncan be driven into super-linear backtracking or into unbounded matcher recursion by a\nsmall crafted input.\u003c/span\u003e\u003c/p\u003e\n\n\u003cp\u003eFor the EMAIL pattern, a long run of local-part characters that is never followed by an\n\u003ccode\u003e@\u003c/code\u003e 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 \u003ccode\u003efind()\u003c/code\u003e call and returns no match, and each doubling of the input\nmultiplies the cost roughly four-fold.\u003c/p\u003e\n\n\u003cp\u003eFor 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 \u003ccode\u003e\u0026amp;\u003c/code\u003e-separated tokens exhausts the thread stack and\ncauses \u003ccode\u003ejava.lang.StackOverflowError\u003c/code\u003e to propagate out of \u003ccode\u003efind()\u003c/code\u003e, terminating the\ncalling thread. On a thread created with a smaller stack (for example \u003ccode\u003e-Xss512k\u003c/code\u003e, typical\nof server worker pools) approximately 1 KB is sufficient.\u003c/p\u003e\n\n\u003cp\u003eIn 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.\u003c/p\u003e\n\n\u003cp\u003eThis issue affects Apache OpenNLP: from 2.0.0 through 2.5.11; from 3.0.0-M1 through\n3.0.0-M5.\u003c/p\u003e\u003cp\u003e\n\n\u003c/p\u003e\u003cp\u003eUsers 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.\u003c/p\u003e\n\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"
            }
          ],
          "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."
        }
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      "metrics": [
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 10,
            "baseSeverity": "CRITICAL",
            "exploitMaturity": "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",
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            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Apache OpenNLP, Apache OpenNLP: ReDoS / stack exhaustion in RegexNameFinderFactory built-in EMAIL and URL patterns",
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    "datePublished": "2026-09-11T17:50:53.639Z",
    "dateReserved": "2026-08-30T07:51:33.177Z",
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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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.