Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.31, parse_form() did not validate the Content-Length header before using it to bound its chunked read of the request body. A negative Content-Length turned the bounded read into a read-until-EOF, so the entire body was loaded into memory in a single read instead of in fixed-size chunks. This vulnerability is fixed in 0.0.31.
CVE-2026-53540
This low-severity CVE scores 3.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 88% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 3.7
- EG Score
- 3.7(medium)
- EPSS
- 12.2%
- KEV
- Not listed
Published
June 15, 2026
Last Modified
June 26, 2026
References (1)
- security-advisories@githubhttps://github.com/Kludex/python-multipart/security/advisories/GHSA-v9pg-7xvm-68hf
Vendor Advisories for CVE-2026-53540(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| python-multipart | 0.0.1 ... 0.0.9 (30 versions) | 0.0.31 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 28× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 09:35 UTCEG score recompute
- 2026-07-05 02:31 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-02 14:51 UTCEG score recompute
- 2026-07-01 15:07 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-29 20:09 UTCEG score recompute
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-29 14:06 UTCEPSS rescore
- 2026-06-28 14:07 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-27 01:26 UTCEG score recompute
- 2026-06-25 13:49 UTCEPSS rescore
- 2026-06-24 14:05 UTCEPSS rescore
- 2026-06-24 06:42 UTCEG score recompute
- 2026-06-23 21:33 UTCEPSS rescore
- 2026-06-23 21:33 UTCEPSS rescore
Show 3 moreShow fewer
- 2026-06-21 10:29 UTCEG score recompute
- 2026-06-18 15:46 UTCEG score recompute
- 2026-06-15 20:46 UTCEG score recompute
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Frequently asked(5)
What is CVE-2026-53540?
When was CVE-2026-53540 disclosed?
Is CVE-2026-53540 actively exploited?
What is the CVSS score of CVE-2026-53540?
How do I remediate CVE-2026-53540?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53540
Is Your Infrastructure Affected by CVE-2026-53540?
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