Python-Multipart: Quadratic-time querystring parsing with semicolon separators causes CPU denial of service
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Kludex | python-multipart | affected |
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| Kludex | Python-multipart |
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| Source | ID | Title |
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Github GHSA |
GHSA-5rvq-cxj2-64vf | python-multipart: Quadratic-time querystring parsing with semicolon separators causes CPU denial of service |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.460% probability within 30 days)
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| Metrics |
ssvc
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| First Time appeared |
Kludex
Kludex python-multipart |
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| Vendors & Products |
Kludex
Kludex python-multipart |
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| Description | Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, when parsing application/x-www-form-urlencoded bodies, QuerystringParser located the field separator with a two step lookup: it first scanned the entire remaining buffer for &, and only when no & existed anywhere ahead did it fall back to scanning for ;. For a body that uses ; as the separator and contains no &, every field iteration performed a full failed & scan over the entire remaining buffer before locating the nearby ;. With N semicolon separated fields in a chunk of size B, this yields O(B^2) byte comparisons per chunk. An attacker can submit a small crafted body of the form a;a;a;... and cause the parser to spend seconds of CPU per request. A handful of concurrent requests can exhaust worker processes. This vulnerability is fixed in 0.0.30. | |
| Title | Python-Multipart: Quadratic-time querystring parsing with semicolon separators causes CPU denial of service | |
| Weaknesses | CWE-400 CWE-407 |
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| References |
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| Metrics |
cvssV3_1
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