CVE-2024-53981
highpriority · track · 0EPSS 0.006 · 50 %ileEURUUSEPSS · scored 2026-10-28
python-multipart is a streaming multipart parser for Python. When parsing form data, python-multipart skips line breaks (CR \r or LF \n) in front of the first boundary and any tailing bytes after the last boundary. This happens one byte at a time and emits a log event each time, which may cause excessive logging for certain inputs. An attacker could abuse this by sending a malicious request with lots of data before the first or after the last boundary, causing high CPU load and stalling the processing thread for a significant amount of time. In case of ASGI application, this could stall the event loop and prevent other requests from being processed, resulting in a denial of service (DoS). This vulnerability is fixed in 0.0.18.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (6)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-59g5-xgcq-4qw3Denial of service (DoS) via deformation `multipart/form-data` boundary2024-12-02ghsa · osvUS
### Summary When parsing form data, `python-multipart` skips line breaks (CR `\r` or LF `\n`) in front of the first boundary and any tailing bytes after the last boundary. This happens one byte at a time and emits a log event each time, which may cause excessive logging for certain inputs. An attacker could abuse this by sending a malicious request with lots of data before the first or after the last boundary, causing high CPU load and stalling the processing thread for a significant amount of time. In case of ASGI application, this could stall the event loop and prevent other requests from being processed, resulting in a denial of service (DoS). ### Impact Applications that use `python-multipart` to parse form data (or use frameworks that do so) are affected. ### Original Report This security issue was reported by: - GitHub security advisory in Starlette on October 30 by @Startr4ck - Email to `python-multipart` maintainer on October 3 by @mnqazi
- PYSEC-2026-1851Denial of service (DoS) via deformation `multipart/form-data` boundary2026-07-07vendor · osvUS
### Summary When parsing form data, `python-multipart` skips line breaks (CR `\r` or LF `\n`) in front of the first boundary and any tailing bytes after the last boundary. This happens one byte at a time and emits a log event each time, which may cause excessive logging for certain inputs. An attacker could abuse this by sending a malicious request with lots of data before the first or after the last boundary, causing high CPU load and stalling the processing thread for a significant amount of time. In case of ASGI application, this could stall the event loop and prevent other requests from being processed, resulting in a denial of service (DoS). ### Impact Applications that use `python-multipart` to parse form data (or use frameworks that do so) are affected. ### Original Report This security issue was reported by: - GitHub security advisory in Starlette on October 30 by @Startr4ck - Email to `python-multipart` maintainer on October 3 by @mnqazi
also known as (7)
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sources
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references (7)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2024-53981cnnvd
- https://github.com/Kludex/python-multipart/commit/c4fe4d3cebc08c660e57dd709af1ffa7059b3177cnnvd
- https://github.com/Kludex/python-multipart/security/advisories/GHSA-59g5-xgcq-4qw3cnnvd
- https://github.com/Kludex/python-multipart/commit/c4fe4d3cebc08c660e57dd709af1ffa7059b3177enisa_euvd
- https://github.com/Kludex/python-multipart/security/advisories/GHSA-59g5-xgcq-4qw3enisa_euvd
- https://github.com/Kludex/python-multipart/commit/c4fe4d3cebc08c660e57dd709af1ffa7059b3177nvd
- https://github.com/Kludex/python-multipart/security/advisories/GHSA-59g5-xgcq-4qw3nvd
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