Vulnerability-Lookup

GHSA-2345-WR3R-CXF2

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-10 15:33

Details

Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

Severity

2.4 (Low)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-18503"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1176"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T14:17:21Z",
    "severity": "LOW"
  },
  "details": "Attacker-controlled CSV samples can trigger super-linear \nregular-expression work during dialect sniffing and consume significant \nCPU when applications pass unbounded input to csv.Sniffer.sniff().",
  "id": "GHSA-2345-wr3r-cxf2",
  "modified": "2026-08-10T15:33:51Z",
  "published": "2026-08-10T15:33:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18503"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/issues/98820"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/pull/153694"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693b"
    },
    {
      "type": "WEB",
      "url": "https://mail.python.org/archives/list/security-announce@python.org/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/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-2026-18503 (GCVE-0-2026-18503)

Vulnerability from cvelistv5 – Published: 2026-08-10 13:45 – Updated: 2026-08-10 17:56

Title

Super-linear CPU usage for unbounded input to csv.Sniffer.sniff()

Summary

Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

Severity

2.4 (Low)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-1176

Assigner

PSF

References

7 references

URL	Tags
https://mail.python.org/archives/list/security-an…	vendor-advisory
https://github.com/python/cpython/pull/153694	patch
https://github.com/python/cpython/issues/98820	issue-tracking
https://github.com/python/cpython/commit/063d4555…	patch
https://github.com/python/cpython/commit/476fb09c…	patch
https://github.com/python/cpython/commit/89f29c76…	patch
https://github.com/python/cpython/commit/b30c7fa9…	patch

Impacted products

1 product

Vendor	Product	Version
Python Software Foundation	CPython	Affected: 0 , < 3.13.15 (python) Affected: 3.14.0 , < 3.14.7 (python) Affected: 3.15.0a1 , < 3.15.0rc1 (python)

Credits

Serhiy Storchaka (https://github.com/serhiy-storchaka) Jack Desert (https://github.com/jackdesert) Sean Gilligan (https://github.com/sg3-141-592) Seth Larson (https://github.com/sethmlarson)

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-18503",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-10T17:56:17.853221Z",
                "version": "2.0.3"
              },
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        "providerMetadata": {
          "dateUpdated": "2026-08-10T17:56:28.336Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "modules": [
            "csv"
          ],
          "product": "CPython",
          "repo": "https://github.com/python/cpython",
          "vendor": "Python Software Foundation",
          "versions": [
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              "status": "affected",
              "version": "0",
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              "status": "affected",
              "version": "3.14.0",
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      "credits": [
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          "lang": "en",
          "type": "remediation developer",
          "value": "Serhiy Storchaka (https://github.com/serhiy-storchaka)"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "Jack Desert (https://github.com/jackdesert)"
        },
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          "type": "reporter",
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        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Seth Larson (https://github.com/sethmlarson)"
        }
      ],
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          "supportingMedia": [
            {
              "type": "text/html",
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          ],
          "value": "Attacker-controlled CSV samples can trigger super-linear \nregular-expression work during dialect sniffing and consume significant \nCPU when applications pass unbounded input to csv.Sniffer.sniff()."
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      ],
      "metrics": [
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          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "LOCAL",
            "baseScore": 2.4,
            "baseSeverity": "LOW",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
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            "vulnAvailabilityImpact": "LOW",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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          "scenarios": [
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        },
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          "tags": [
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        },
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          "tags": [
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        }
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    "datePublished": "2026-08-10T13:45:31.618Z",
    "dateReserved": "2026-07-31T16:35:42.902Z",
    "dateUpdated": "2026-08-10T17:56:28.336Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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.

Action not permitted

GHSA-2345-WR3R-CXF2

CVE-2026-18503 (GCVE-0-2026-18503)

Tags

Sightings

Nomenclature