CVE Explorer

CVE-2026-53538

Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, QuerystringParser treated ; as a field separator in application/x-www-form-urlencoded bodies, in addition to &. The WHATWG URL standard, modern browsers, and Python's urllib.parse (since the CVE-2021-23336 fix) treat only & as a separator. This creates a parser differential: the same bytes are tokenized into different fields than a WHATWG compliant intermediary would produce, allowing an attacker to smuggle extra form

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:037ea87a72a7e31e40aa30a67b0b2b443b9f52836c2842a9d216f3edc1d36e1d

Known exploited

Not asserted

Disputed

Stale source

Conflicts

Preserved source conflicts

No provider value was silently selected as the winner.

cwe · 2 assertions

{"cweId":"CWE-444","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/problemTypes/1/descriptions/0

{"cweId":"CWE-436","description":"CWE-436: Interpretation Conflict","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/problemTypes/0/descriptions/0

Affected products and versions

1 source assertion

{"product":"python-multipart","vendor":"Kludex","versions":[{"status":"affected","version":"< 0.0.30"}]}

cve_program_cvelist_v5affected
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion

{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/metrics/0/cvssV3_1

CWE assertions

2 source assertions

{"cweId":"CWE-444","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/problemTypes/1/descriptions/0

{"cweId":"CWE-436","description":"CWE-436: Interpretation Conflict","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/problemTypes/0/descriptions/0

Source references

1 source assertion

{"name":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-6jv3-5f52-599m","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Kludex/python-multipart/security/advisories/GHSA-6jv3-5f52-599m"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:2c796a1fca4969de1798c7cafc9e40c3b3580066108b5c8b2489b0d2d2cf303f · sha256:403cc392c55decd6… · /containers/cna/references/0

Attribution and limitations

CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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