Vulnerability-Lookup

GHSA-7QJ2-Q5C8-CXX5

Vulnerability from github – Published: 2026-07-09 18:31 – Updated: 2026-07-09 21:31

Details

The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.

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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-15308"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-09T17:16:58Z",
    "severity": "CRITICAL"
  },
  "details": "The incremental HTML parser (html.parser.HTMLParser) allows for CPU\ndenial-of-service through repeated unterminated markup declarations when\nprocessing uncontrolled data.",
  "id": "GHSA-7qj2-q5c8-cxx5",
  "modified": "2026-07-09T21:31:19Z",
  "published": "2026-07-09T18:31:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-15308"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/153030"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/153031"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/09/4"
    }
  ],
  "schema_version": "1.4.0",
  "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/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-15308 (GCVE-0-2026-15308)

Vulnerability from cvelistv5 – Published: 2026-07-09 17:10 – Updated: 2026-07-09 19:32

Title

Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations

Summary

The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-400

Assigner

PSF

References

8 references

URL	Tags
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/pull/153031	patch
https://github.com/python/cpython/issues/153030	issue-tracking
https://github.com/python/cpython/commit/07efb081…	patch
https://github.com/python/cpython/commit/7933f4bf…	patch
https://github.com/python/cpython/commit/bcf98ddb…	patch
https://github.com/python/cpython/commit/e9f92ac0…	patch
http://www.openwall.com/lists/oss-security/2026/07/09/4

Impacted products

1 product

Vendor	Product	Version
Python Software Foundation	CPython	Affected: 0 , < 3.15.0 (python)

Credits

Edward-x (https://github.com/YLChen-007) Serhiy Storchaka (https://github.com/serhiy-storchaka) Gregory P. Smith (https://github.com/gpshead) Seth Larson (https://github.com/sethmlarson)

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        "metrics": [
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            "other": {
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                "id": "CVE-2026-15308",
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                  },
                  {
                    "Technical Impact": "partial"
                  }
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                "timestamp": "2026-07-09T17:31:19.781935Z",
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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.

Action not permitted

GHSA-7QJ2-Q5C8-CXX5

CVE-2026-15308 (GCVE-0-2026-15308)

Tags

Sightings

Nomenclature