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Vulnerabilities

Vulnerability · CVE-2026-42561

Python-Multipart is a streaming multipart parser for Python.

Published May 13, 2026 · catalog updated Aug 7, 2026 · Python-Multipart is a streaming

Check if you run it

No confirmed exploitation is on record for CVE-2026-42561. EPSS is 0.85%. Act only if a listed version of Python-Multipart is a streaming is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Python-Multipart is a streaming).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.85%
Remediation
Advisory link
Affected products
See sources for product scope

Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-42561

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-42561. EPSS is 0.85%. Act only if a listed version of Python-Multipart is a streaming is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-606; CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.85%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 13, 2026 · NIST NVD

    Detected

    Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating

  2. Aug 7, 2026 · NIST NVD

    Updated

    Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating

Sources

  • CVE.orgVulnerability recordCVE-2026-42561

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-42561

    30-day exploitation probability 0.8%

    first.org
  • NIST NVDVulnerability recordCVE-2026-42561

    Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the si

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.