How severe is GHSA-pp6c-gr5w-3c5g?

GHSA-pp6c-gr5w-3c5g has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-pp6c-gr5w-3c5g?

GHSA-pp6c-gr5w-3c5g affects the following packages: python-multipart (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-pp6c-gr5w-3c5g?

Update python-multipart to 0.0.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pp6c-gr5w-3c5g is resolved across your whole dependency graph.

How do I detect GHSA-pp6c-gr5w-3c5g in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for python-multipart. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-pp6c-gr5w-3c5g if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-pp6c-gr5w-3c5g?

O3 pinpoints whether GHSA-pp6c-gr5w-3c5g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-pp6c-gr5w-3c5g actively exploited in the wild?

No public exploit code has been indexed for GHSA-pp6c-gr5w-3c5g yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is GHSA-pp6c-gr5w-3c5g?

GHSA-pp6c-gr5w-3c5g is classified as CWE-770 (CWE-770), CWE-606 (CWE-606). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-pp6c-gr5w-3c5g published, and has it been updated?

GHSA-pp6c-gr5w-3c5g was published on May 6, 2026 and was last updated on July 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

HIGH severity

GHSA-pp6c-gr5w-3c5g

HIGH

GHSA-pp6c-gr5w-3c5g is a high-severity (CVSS 7.5) CWE-770 vulnerability in python-multipart. O3 Security confirms whether GHSA-pp6c-gr5w-3c5g is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

python-multipart has Denial of Service via unbounded multipart part headers

Also known asCVE-2026-42561PYSEC-2026-3039

Published

May 6, 2026

Updated

Jul 13, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Jul 13, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐍python-multipart

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

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.

Impact

Applications that parse attacker-controlled multipart/form-data with affected versions of python-multipart can experience CPU exhaustion. ASGI applications using Starlette, FastAPI, or other frameworks that invoke python-multipart may have worker or event-loop delays while processing malicious upload requests.

Details

The affected parser states are HEADER_FIELD_START, HEADER_FIELD, HEADER_VALUE_START, HEADER_VALUE, and HEADER_VALUE_ALMOST_DONE. The issue can be triggered by:

A multipart part with an oversized individual header value.
A multipart part with many repeated header lines or an unterminated header block.

Both variants are addressed by enforcing default parser limits for maximum header count and maximum header size.

Mitigation

Upgrade to python-multipart 0.0.27 or later.

If upgrading is not immediately possible, reduce exposure by enforcing request body size limits at the server, proxy, or framework layer. This is only a mitigation; affected versions of python-multipart still parse multipart part headers without the default header count and header size limits.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`python-multipart`	all versions	0.0.27

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for python-multipart. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update python-multipart to 0.0.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pp6c-gr5w-3c5g is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-pp6c-gr5w-3c5g is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-pp6c-gr5w-3c5g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary `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. ### Impact Applications that parse attacker-controlled `multipart/form-data` with affected versions of `python-multipart` can experience

O3 Security · Impact-Aware SCA

Is GHSA-pp6c-gr5w-3c5g in your dependencies?

O3 detects GHSA-pp6c-gr5w-3c5g across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works