Vulnerability-Lookup

GHSA-J8R3-CGHJ-9JHG

Vulnerability from github – Published: 2025-05-15 15:31 – Updated: 2025-06-03 15:31

Details

There is an issue in CPython when using bytes.decode("unicode_escape", error="ignore|replace"). If you are not using the "unicode_escape" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.

Severity

5.9 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2025-4516"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-05-15T14:15:31Z",
    "severity": "MODERATE"
  },
  "details": "There is an issue in CPython when using `bytes.decode(\"unicode_escape\", error=\"ignore|replace\")`. If you are not using the \"unicode_escape\" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.",
  "id": "GHSA-j8r3-cghj-9jhg",
  "modified": "2025-06-03T15:31:24Z",
  "published": "2025-05-15T15:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-4516"
    },
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      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/133767"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/129648"
    },
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      "url": "https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a571292"
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    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429d"
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    {
      "type": "WEB",
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      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2025/05/16/4"
    },
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      "url": "http://www.openwall.com/lists/oss-security/2025/05/19/1"
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  "schema_version": "1.4.0",
  "severity": [
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      "score": "CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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",
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}

CVE-2025-4516 (GCVE-0-2025-4516)

Vulnerability from cvelistv5 – Published: 2025-05-15 13:29 – Updated: 2026-07-31 14:02

Title

Use-after-free in "unicode_escape" decoder with error handler

Summary

There is an issue in CPython when using `bytes.decode("unicode_escape", error="ignore|replace")`. If you are not using the "unicode_escape" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-05-15 14:18 UTC

CWE

CWE-416 - Use After Free

Assigner

PSF CNA under the mitre root

CNA scorecard B 80/100 over 29 records in the last 180 days details

References

12 references

URL	Tags
https://github.com/python/cpython/issues/133767	issue-tracking
https://github.com/python/cpython/pull/129648	patch
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/commit/69b4387f…	patch
https://github.com/python/cpython/commit/9f69a586…	patch
https://github.com/python/cpython/commit/4398b788…	patch
https://github.com/python/cpython/commit/6279eb8c…	patch
https://github.com/python/cpython/commit/73b3040f…	patch
https://github.com/python/cpython/commit/8d35fd1b…	patch
https://github.com/python/cpython/commit/ab9893c4…	patch
http://www.openwall.com/lists/oss-security/2025/05/16/4
http://www.openwall.com/lists/oss-security/2025/05/19/1

Impacted products

1 product

Vendor	Product	Version
Python Software Foundation	CPython	Affected: 0 , < 3.9.23 (python) Affected: 3.10.0 , < 3.10.18 (python) Affected: 3.11.0 , < 3.11.13 (python) Affected: 3.12.0 , < 3.12.11 (python) Affected: 3.13.0 , < 3.13.4 (python) Affected: 3.14.0a1 , < 3.14.0b2 (python)

Show details on NVD website

JSON

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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.

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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.

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