CVE-2026-4539 (GCVE-0-2026-4539)

Vulnerability from cvelistv5 – Published: 2026-03-22 05:35 – Updated: 2026-03-23 16:08
VLAI
Title
pygments archetype.py AdlLexer redos
Summary
A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.
Severity
4.8 (Medium)
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
3.3 (Low)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
3.3 (Low)
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-23 16:08 UTC
CWE
  • CWE-1333 - Inefficient Regular Expression Complexity
  • CWE-400 - Resource Consumption
Assigner
VulDB CNA under the mitre root
CNA scorecard B 82/100 over 3677 records in the last 180 days details
References
URL Tags
https://vuldb.com/?id.352327 vdb-entrytechnical-description
https://vuldb.com/?ctiid.352327 signaturepermissions-required
https://vuldb.com/?submit.774685 third-party-advisory
https://github.com/pygments/pygments/issues/3058 exploitissue-tracking
https://github.com/pygments/pygments/ product
Impacted products
Vendor Product Version CPE status
n/a pygments Affected: 2.19.0
Affected: 2.19.1
Affected: 2.19.2
Credits
ybdesire (VulDB User)
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-4539",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-23T16:08:35.203035Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-23T16:08:49.809Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "pygments",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "2.19.0"
            },
            {
              "status": "affected",
              "version": "2.19.1"
            },
            {
              "status": "affected",
              "version": "2.19.2"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "ybdesire (VulDB User)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "baseScore": 4.8,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P",
            "version": "4.0"
          }
        },
        {
          "cvssV3_1": {
            "baseScore": 3.3,
            "baseSeverity": "LOW",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R",
            "version": "3.1"
          }
        },
        {
          "cvssV3_0": {
            "baseScore": 3.3,
            "baseSeverity": "LOW",
            "vectorString": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R",
            "version": "3.0"
          }
        },
        {
          "cvssV2_0": {
            "baseScore": 1.7,
            "vectorString": "AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR",
            "version": "2.0"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1333",
              "description": "Inefficient Regular Expression Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-22T05:35:12.096Z",
        "orgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
        "shortName": "VulDB"
      },
      "references": [
        {
          "name": "VDB-352327 | pygments archetype.py AdlLexer redos",
          "tags": [
            "vdb-entry",
            "technical-description"
          ],
          "url": "https://vuldb.com/?id.352327"
        },
        {
          "name": "VDB-352327 | CTI Indicators (IOB, IOC, TTP, IOA)",
          "tags": [
            "signature",
            "permissions-required"
          ],
          "url": "https://vuldb.com/?ctiid.352327"
        },
        {
          "name": "Submit #774685 | pygments \u003c=2.19.2 Denial of Service",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://vuldb.com/?submit.774685"
        },
        {
          "tags": [
            "exploit",
            "issue-tracking"
          ],
          "url": "https://github.com/pygments/pygments/issues/3058"
        },
        {
          "tags": [
            "product"
          ],
          "url": "https://github.com/pygments/pygments/"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-03-21T00:00:00.000Z",
          "value": "Advisory disclosed"
        },
        {
          "lang": "en",
          "time": "2026-03-21T01:00:00.000Z",
          "value": "VulDB entry created"
        },
        {
          "lang": "en",
          "time": "2026-03-21T10:15:34.000Z",
          "value": "VulDB entry last update"
        }
      ],
      "title": "pygments archetype.py AdlLexer redos"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
    "assignerShortName": "VulDB",
    "cveId": "CVE-2026-4539",
    "datePublished": "2026-03-22T05:35:12.096Z",
    "dateReserved": "2026-03-21T09:10:23.929Z",
    "dateUpdated": "2026-03-23T16:08:49.809Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-4539",
      "date": "2026-10-10",
      "epss": "0.00159",
      "percentile": "0.04504"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "pygments",
                "vendor": "n/a",
                "versions": [
                  {
                    "status": "affected",
                    "version": "2.19.0"
                  },
                  {
                    "status": "affected",
                    "version": "2.19.1"
                  },
                  {
                    "status": "affected",
                    "version": "2.19.2"
                  }
                ]
              }
            ],
            "source": "cna@vuldb.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet."
          },
          {
            "lang": "es",
            "value": "Una falla de seguridad ha sido descubierta en pygments hasta la versi\u00f3n 2.19.2. El elemento afectado es la funci\u00f3n AdlLexer del archivo pygments/lexers/archetype.py. La manipulaci\u00f3n resulta en una complejidad ineficiente de la expresi\u00f3n regular. El ataque solo es posible con acceso local. El exploit ha sido publicado y puede ser utilizado para ataques. El proyecto fue informado del problema tempranamente a trav\u00e9s de un informe de problema, pero a\u00fan no ha respondido."
          }
        ],
        "id": "CVE-2026-4539",
        "lastModified": "2026-06-17T10:56:46.690",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "LOW",
              "cvssData": {
                "accessComplexity": "LOW",
                "accessVector": "LOCAL",
                "authentication": "SINGLE",
                "availabilityImpact": "PARTIAL",
                "baseScore": 1.7,
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "vectorString": "AV:L/AC:L/Au:S/C:N/I:N/A:P",
                "version": "2.0"
              },
              "exploitabilityScore": 3.1,
              "impactScore": 2.9,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "cna@vuldb.com",
              "type": "Secondary",
              "userInteractionRequired": false
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "LOW",
                "baseScore": 3.3,
                "baseSeverity": "LOW",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 1.4,
              "source": "cna@vuldb.com",
              "type": "Secondary"
            }
          ],
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "LOCAL",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 1.9,
                "baseSeverity": "LOW",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "PROOF_OF_CONCEPT",
                "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": "LOW",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "NONE",
                "subIntegrityImpact": "NONE",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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": "LOW",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "cna@vuldb.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-4539",
                "options": [
                  {
                    "exploitation": "poc"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-23T16:08:35.203035Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-03-22T06:16:20.913",
        "references": [
          {
            "source": "cna@vuldb.com",
            "url": "https://github.com/pygments/pygments/"
          },
          {
            "source": "cna@vuldb.com",
            "url": "https://github.com/pygments/pygments/issues/3058"
          },
          {
            "source": "cna@vuldb.com",
            "url": "https://vuldb.com/?ctiid.352327"
          },
          {
            "source": "cna@vuldb.com",
            "url": "https://vuldb.com/?id.352327"
          },
          {
            "source": "cna@vuldb.com",
            "url": "https://vuldb.com/?submit.774685"
          }
        ],
        "sourceIdentifier": "cna@vuldb.com",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-400"
              },
              {
                "lang": "en",
                "value": "CWE-1333"
              }
            ],
            "source": "cna@vuldb.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-06-28T07:39:37+00:00",
      "cve": "CVE-2026-4539",
      "id": "CVE-2026-4539",
      "initial_release_date": "2026-03-22T05:35:12.096000+00:00",
      "product_status:known_affected": "89",
      "product_status:known_not_affected": "31",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "pygments: Pygments: Denial of Service via inefficient regular expression processing in AdlLexer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4539.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2026-09-11T01:45:06Z",
      "cve": "CVE-2026-4539",
      "id": "CVE-2026-4539",
      "initial_release_date": "2026-03-26T17:10:38Z",
      "product_status:known_affected": "481",
      "product_status:recommended": "26",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-4539",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-4539.json",
      "version": "11"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-4539",
                    "options": [
                      {
                        "Exploitation": "poc"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-03-23T16:08:35.203035Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-03-23T16:08:43.157Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "pygments",
              "vendor": "n/a",
              "versions": [
                {
                  "status": "affected",
                  "version": "2.19.0"
                },
                {
                  "status": "affected",
                  "version": "2.19.1"
                },
                {
                  "status": "affected",
                  "version": "2.19.2"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "ybdesire (VulDB User)"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet."
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "baseScore": 4.8,
                "baseSeverity": "MEDIUM",
                "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P",
                "version": "4.0"
              }
            },
            {
              "cvssV3_1": {
                "baseScore": 3.3,
                "baseSeverity": "LOW",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R",
                "version": "3.1"
              }
            },
            {
              "cvssV3_0": {
                "baseScore": 3.3,
                "baseSeverity": "LOW",
                "vectorString": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R",
                "version": "3.0"
              }
            },
            {
              "cvssV2_0": {
                "baseScore": 1.7,
                "vectorString": "AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR",
                "version": "2.0"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-1333",
                  "description": "Inefficient Regular Expression Complexity",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            },
            {
              "descriptions": [
                {
                  "cweId": "CWE-400",
                  "description": "Resource Consumption",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-03-22T05:35:12.096Z",
            "orgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
            "shortName": "VulDB"
          },
          "references": [
            {
              "name": "VDB-352327 | pygments archetype.py AdlLexer redos",
              "tags": [
                "vdb-entry",
                "technical-description"
              ],
              "url": "https://vuldb.com/?id.352327"
            },
            {
              "name": "VDB-352327 | CTI Indicators (IOB, IOC, TTP, IOA)",
              "tags": [
                "signature",
                "permissions-required"
              ],
              "url": "https://vuldb.com/?ctiid.352327"
            },
            {
              "name": "Submit #774685 | pygments \u003c=2.19.2 Denial of Service",
              "tags": [
                "third-party-advisory"
              ],
              "url": "https://vuldb.com/?submit.774685"
            },
            {
              "tags": [
                "exploit",
                "issue-tracking"
              ],
              "url": "https://github.com/pygments/pygments/issues/3058"
            },
            {
              "tags": [
                "product"
              ],
              "url": "https://github.com/pygments/pygments/"
            }
          ],
          "timeline": [
            {
              "lang": "en",
              "time": "2026-03-21T00:00:00.000Z",
              "value": "Advisory disclosed"
            },
            {
              "lang": "en",
              "time": "2026-03-21T01:00:00.000Z",
              "value": "VulDB entry created"
            },
            {
              "lang": "en",
              "time": "2026-03-21T10:15:34.000Z",
              "value": "VulDB entry last update"
            }
          ],
          "title": "pygments archetype.py AdlLexer redos"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "1af790b2-7ee1-4545-860a-a788eba489b5",
        "assignerShortName": "VulDB",
        "cveId": "CVE-2026-4539",
        "datePublished": "2026-03-22T05:35:12.096Z",
        "dateReserved": "2026-03-21T09:10:23.929Z",
        "dateUpdated": "2026-03-23T16:08:49.809Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.