Vulnerability-Lookup

UBUNTU-CVE-2026-67987 (CVE-2026-67987)

Vulnerability from osv_ubuntu – Published: 2026-09-29 20:17 – Updated: 2026-09-29 20:17 – Source website

Details

crmne/ruby_llm at commit fa6f279847d6d7027814539d9c0dfc3bbdfd2a83 contains polynomial-time regular expression denial-of-service conditions in think-tag response parsing on Ruby 3.1.x. A malicious or anomalous model response containing many unterminated tags can cause excessive CPU consumption in two consecutive regular expressions and delay chat-completion processing

Severity

7.5 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-67987	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-67987	REPORT
	https://github.com/crmne/ruby_llm	REPORT
	https://github.com/crmne/ruby_llm/blob/fa6f279847…	REPORT
	https://github.com/crmne/ruby_llm/commit/5e88411f…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-llm",
            "binary_version": "1.16.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.10",
        "name": "ruby-llm",
        "purl": "pkg:deb/ubuntu/ruby-llm@1.16.0-2?arch=source\u0026distro=stonking"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.16.0-2"
      ]
    }
  ],
  "aliases": [],
  "details": "crmne/ruby_llm at commit fa6f279847d6d7027814539d9c0dfc3bbdfd2a83 contains polynomial-time regular expression denial-of-service conditions in think-tag response parsing on Ruby 3.1.x. A malicious or anomalous model response containing many unterminated \u003cthink\u003e tags can cause excessive CPU consumption in two consecutive regular expressions and delay chat-completion processing",
  "id": "UBUNTU-CVE-2026-67987",
  "modified": "2026-09-29T20:17:00Z",
  "published": "2026-09-29T20:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-67987"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-67987"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/crmne/ruby_llm"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/crmne/ruby_llm/blob/fa6f279847d6d7027814539d9c0dfc3bbdfd2a83/lib/ruby_llm/protocols/chat_completions/chat.rb#L355-L356"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/crmne/ruby_llm/commit/5e88411f171721b381853fa77d254e266dcf6ad8"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-67987"
  ]
}

CVE-2026-67987 (GCVE-0-2026-67987)

Vulnerability from cvelistv5 – Published: 2026-09-29 00:00 – Updated: 2026-10-01 15:22

Summary

crmne/ruby_llm at commit fa6f279847d6d7027814539d9c0dfc3bbdfd2a83 contains polynomial-time regular expression denial-of-service conditions in think-tag response parsing on Ruby 3.1.x. A malicious or anomalous model response containing many unterminated <think> tags can cause excessive CPU consumption in two consecutive regular expressions and delay chat-completion processing

Severity

7.5 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-01 15:21 UTC

CWE

n/a
CWE-1333 - Inefficient Regular Expression Complexity

Assigner

mitre CNA under the mitre root

CNA scorecard E 29/100 over 2357 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/crmne/ruby_llm
https://github.com/crmne/ruby_llm/blob/fa6f279847…
https://github.com/crmne/ruby_llm/commit/5e88411f…

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 7.5,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-67987",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-01T15:21:55.298371Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-1333",
                "description": "CWE-1333 Inefficient Regular Expression Complexity",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-01T15:22:56.624Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "crmne/ruby_llm at commit fa6f279847d6d7027814539d9c0dfc3bbdfd2a83 contains polynomial-time regular expression denial-of-service conditions in think-tag response parsing on Ruby 3.1.x. A malicious or anomalous model response containing many unterminated \u003cthink\u003e tags can cause excessive CPU consumption in two consecutive regular expressions and delay chat-completion processing"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-29T19:51:47.545Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/crmne/ruby_llm"
        },
        {
          "url": "https://github.com/crmne/ruby_llm/blob/fa6f279847d6d7027814539d9c0dfc3bbdfd2a83/lib/ruby_llm/protocols/chat_completions/chat.rb#L355-L356"
        },
        {
          "url": "https://github.com/crmne/ruby_llm/commit/5e88411f171721b381853fa77d254e266dcf6ad8"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-67987",
    "datePublished": "2026-09-29T00:00:00.000Z",
    "dateReserved": "2026-07-30T00:00:00.000Z",
    "dateUpdated": "2026-10-01T15:22:56.624Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
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.

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