Vulnerability-Lookup

GHSA-G94X-JRVX-M3CV

Vulnerability from github – Published: 2026-11-03 21:32 – Updated: 2026-11-03 21:32

Details

Inefficient Regular Expression Complexity (CWE-1333) in generate_regex() (whatstk/whatsapp/parser.py) in whatstk from 0.2.0 before 0.9.0 allows a party that supplies a chat export to consume the CPU of the process that parses it for an unbounded time, because the function builds the header regular expression by replacing each %x code with its named capture group and leaves every other character of the header format in the pattern unescaped. A header whose date separator is a regular expression metacharacter therefore alters the pattern instead of matching itself: a separator of + quantifies the preceding capture group, giving (?P\d{1,2})+(?P\d{1,2})+(?P\d{2,4}), and a run of digits that cannot complete the header then makes the engine try every way of partitioning that run. Header auto detection is enabled by default and derives the format from the text of the file, so the separator is taken from the export itself and no header format has to be passed by the caller. Separators of (, ) and \ instead raise re.PatternError, separators of *, | and ? raise TypeError, and separators of ^ and $ raise KeyError, none of which the library catches. This results in the parse of a file of a few hundred bytes consuming CPU without completing, or in an uncaught exception in the calling program.

Severity

6.7 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-121577"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-11-03T20:18:13Z",
    "severity": "MODERATE"
  },
  "details": "Inefficient Regular Expression Complexity (CWE-1333) in generate_regex() (whatstk/whatsapp/parser.py) in whatstk from 0.2.0 before 0.9.0 allows a party that supplies a chat export to consume the CPU of the process that parses it for an unbounded time, because the function builds the header regular expression by replacing each %x code with its named capture group and leaves every other character of the header format in the pattern unescaped. A header whose date separator is a regular expression metacharacter therefore alters the pattern instead of matching itself: a separator of + quantifies the preceding capture group, giving (?P\u003cday\u003e\\d{1,2})+(?P\u003cmonth\u003e\\d{1,2})+(?P\u003cyear\u003e\\d{2,4}), and a run of digits that cannot complete the header then makes the engine try every way of partitioning that run. Header auto detection is enabled by default and derives the format from the text of the file, so the separator is taken from the export itself and no header format has to be passed by the caller. Separators of (, ) and \\ instead raise re.PatternError, separators of *, | and ? raise TypeError, and separators of ^ and $ raise KeyError, none of which the library catches. This results in the parse of a file of a few hundred bytes consuming CPU without completing, or in an uncaught exception in the calling program.",
  "id": "GHSA-g94x-jrvx-m3cv",
  "modified": "2026-11-03T21:32:13Z",
  "published": "2026-11-03T21:32:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121577"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lucasrodes/whatstk/pull/181"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lucasrodes/whatstk/commit/01d66d8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lucasrodes/whatstk/releases/tag/v0.9.0"
    },
    {
      "type": "WEB",
      "url": "https://secur0.com/en/cna/cve-list/cve-2026-121577-whatstk-header-regex-redos"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-121577 (GCVE-0-2026-121577)

Vulnerability from cvelistv5 – Published: 2026-11-03 19:52 – Updated: 2026-11-03 19:52 X_Open Source

Title

Unescaped header separators in whatstk build a regular expression that backtracks exponentially

Summary

Inefficient Regular Expression Complexity (CWE-1333) in generate_regex() (whatstk/whatsapp/parser.py) in whatstk from 0.2.0 before 0.9.0 allows a party that supplies a chat export to consume the CPU of the process that parses it for an unbounded time, because the function builds the header regular expression by replacing each %x code with its named capture group and leaves every other character of the header format in the pattern unescaped. A header whose date separator is a regular expression metacharacter therefore alters the pattern instead of matching itself: a separator of + quantifies the preceding capture group, giving (?P<day>\d{1,2})+(?P<month>\d{1,2})+(?P<year>\d{2,4}), and a run of digits that cannot complete the header then makes the engine try every way of partitioning that run. Header auto detection is enabled by default and derives the format from the text of the file, so the separator is taken from the export itself and no header format has to be passed by the caller. Separators of (, ) and \ instead raise re.PatternError, separators of *, | and ? raise TypeError, and separators of ^ and $ raise KeyError, none of which the library catches. This results in the parse of a file of a few hundred bytes consuming CPU without completing, or in an uncaught exception in the calling program.

Severity

6.7 (Medium)


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

CWE

CWE-1333 - Inefficient Regular Expression Complexity

Assigner

Secur0 CNA under the INCIBE root

CNA scorecard A 99/100 over 46 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/lucasrodes/whatstk/pull/181	patch
https://github.com/lucasrodes/whatstk/commit/01d66d8	patch
https://github.com/lucasrodes/whatstk/releases/ta…	release-notes
https://secur0.com/en/cna/cve-list/cve-2026-12157…	third-party-advisorytechnical-description

Impacted products

1 product

Vendor	Product	Version
lucasrodes	whatstk	Affected: 0.2.0 , < 0.9.0 (semver) cpe:2.3:a:lucasrodes:whatstk::::::python::*

Credits

m.gongora.carriedo Xoán M. Otero Jorge Darío Rivas Secur0 CNA Lucas Rodés-Guirao

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        {
          "collectionURL": "https://pypi.org",
          "defaultStatus": "unaffected",
          "packageName": "whatstk",
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            "whatstk/whatsapp/auto_header.py"
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          "vendor": "lucasrodes",
          "versions": [
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                  "criteria": "cpe:2.3:a:lucasrodes:whatstk:*:*:*:*:*:python:*:*",
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          "type": "analyst",
          "value": "Xo\u00e1n M. Otero Jorge"
        },
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          "lang": "en",
          "type": "analyst",
          "value": "Dar\u00edo Rivas"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Secur0 CNA"
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          "lang": "en",
          "type": "remediation developer",
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            "subIntegrityImpact": "NONE",
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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.
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