Vulnerability-Lookup

UBUNTU-CVE-2026-76875 (CVE-2026-76875)

Vulnerability from osv_ubuntu – Published: 2026-09-29 13:17 – Updated: 2026-09-29 13:17 – Source website

Details

PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.

Severity

5.3 (Medium)


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

6.3 (Medium)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-76875	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-76875	REPORT
	https://doc.pypy.org/release-v8.0.0.html	REPORT
	https://github.com/pypy/pypy/releases/tag/release…	REPORT
	https://github.com/pypy/pypy/releases/tag/release…	REPORT
	https://www.vulncheck.com/advisories/pypy-pyexpat…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pypy3",
            "binary_version": "7.3.1+dfsg-4ubuntu0.1"
          },
          {
            "binary_name": "pypy3-lib",
            "binary_version": "7.3.1+dfsg-4ubuntu0.1"
          },
          {
            "binary_name": "pypy3-lib-testsuite",
            "binary_version": "7.3.1+dfsg-4ubuntu0.1"
          },
          {
            "binary_name": "pypy3-tk",
            "binary_version": "7.3.1+dfsg-4ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "pypy3",
        "purl": "pkg:deb/ubuntu/pypy3@7.3.1+dfsg-4ubuntu0.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.1.1+dfsg-1",
        "7.2.0+dfsg-1",
        "7.3.0+dfsg-1",
        "7.3.0+dfsg-1ubuntu2",
        "7.3.0+dfsg-1ubuntu3",
        "7.3.1+dfsg-4",
        "7.3.1+dfsg-4ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pypy3",
            "binary_version": "7.3.9+dfsg-1ubuntu0.1"
          },
          {
            "binary_name": "pypy3-lib",
            "binary_version": "7.3.9+dfsg-1ubuntu0.1"
          },
          {
            "binary_name": "pypy3-lib-testsuite",
            "binary_version": "7.3.9+dfsg-1ubuntu0.1"
          },
          {
            "binary_name": "pypy3-tk",
            "binary_version": "7.3.9+dfsg-1ubuntu0.1"
          },
          {
            "binary_name": "pypy3-venv",
            "binary_version": "7.3.9+dfsg-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "pypy3",
        "purl": "pkg:deb/ubuntu/pypy3@7.3.9+dfsg-1ubuntu0.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.3.5+dfsg-2",
        "7.3.7+dfsg-1",
        "7.3.7+dfsg-4",
        "7.3.7+dfsg-5",
        "7.3.8+dfsg-2",
        "7.3.9+dfsg-1",
        "7.3.9+dfsg-1ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pypy3",
            "binary_version": "7.3.15+dfsg-1build3"
          },
          {
            "binary_name": "pypy3-lib",
            "binary_version": "7.3.15+dfsg-1build3"
          },
          {
            "binary_name": "pypy3-lib-testsuite",
            "binary_version": "7.3.15+dfsg-1build3"
          },
          {
            "binary_name": "pypy3-tk",
            "binary_version": "7.3.15+dfsg-1build3"
          },
          {
            "binary_name": "pypy3-venv",
            "binary_version": "7.3.15+dfsg-1build3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "pypy3",
        "purl": "pkg:deb/ubuntu/pypy3@7.3.15+dfsg-1build3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.3.12+dfsg-1",
        "7.3.13+dfsg-1",
        "7.3.14+dfsg-1",
        "7.3.15+dfsg-1",
        "7.3.15+dfsg-1build2",
        "7.3.15+dfsg-1build3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "pypy3",
            "binary_version": "7.3.20+dfsg-4"
          },
          {
            "binary_name": "pypy3-lib",
            "binary_version": "7.3.20+dfsg-4"
          },
          {
            "binary_name": "pypy3-lib-testsuite",
            "binary_version": "7.3.20+dfsg-4"
          },
          {
            "binary_name": "pypy3-tk",
            "binary_version": "7.3.20+dfsg-4"
          },
          {
            "binary_name": "pypy3-venv",
            "binary_version": "7.3.20+dfsg-4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "pypy3",
        "purl": "pkg:deb/ubuntu/pypy3@7.3.20+dfsg-4?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "7.3.20+dfsg-3",
        "7.3.20+dfsg-4"
      ]
    }
  ],
  "aliases": [],
  "details": "PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module\u0027s ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy\u0027s tracing garbage collector can free the parent\u0027s C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.",
  "id": "UBUNTU-CVE-2026-76875",
  "modified": "2026-09-29T13:17:00Z",
  "published": "2026-09-29T13:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-76875"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-76875"
    },
    {
      "type": "REPORT",
      "url": "https://doc.pypy.org/release-v8.0.0.html"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pypy/pypy/releases/tag/release-pypy3.11-v8.0.0"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/pypy/pypy/releases/tag/release-pypy3.12-v8.0.0"
    },
    {
      "type": "REPORT",
      "url": "https://www.vulncheck.com/advisories/pypy-pyexpat-externalentityparsercreate-use-after-free"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-76875"
  ]
}

CVE-2026-76875 (GCVE-0-2026-76875)

Vulnerability from cvelistv5 – Published: 2026-09-29 12:45 – Updated: 2026-10-02 12:07 X_Open Source

Title

PyPy pyexpat ExternalEntityParserCreate Use-After-Free

Summary

Severity

6.3 (Medium)


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

5.3 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-02 12:07 UTC

CWE

CWE-416 - Use After Free

Assigner

VulnCheck mitre root Scorecard

References

4 references

URL	Tags
https://doc.pypy.org/release-v8.0.0.html	release-notes
https://github.com/pypy/pypy/releases/tag/release…	patch
https://github.com/pypy/pypy/releases/tag/release…	patch
https://www.vulncheck.com/advisories/pypy-pyexpat…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
PyPy	PyPy	Affected: 0 , < 3.11.16 (semver) Affected: 3.12.0 , < 3.12.14 (semver)

Date Public

2026-09-19 00:00

Credits

Fabian Wahle (Hap Security) VulnCheck

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-76875",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-02T12:07:14.237053Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
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        "providerMetadata": {
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    "cna": {
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          "packageURL": "pkg:github/pypy/pypy",
          "product": "PyPy",
          "repo": "https://github.com/pypy/pypy",
          "vendor": "PyPy",
          "versions": [
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              "lessThan": "3.11.16",
              "status": "affected",
              "version": "0",
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              "status": "affected",
              "version": "3.12.0",
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      "credits": [
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      "metrics": [
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          "cvssV4_0": {
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
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            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
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            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.
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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.

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.

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Action not permitted

UBUNTU-CVE-2026-76875 (CVE-2026-76875)

CVE-2026-76875 (GCVE-0-2026-76875)

Tags

Sightings

Nomenclature

Related by attack behaviour