Vulnerability in python-multipart (CVE-2026-53540)
Summary
Vulnerability in python-multipart (CVE-2026-53540). Risk of unauthorized operations or information disclosure. Exploitable via MultipartParser. Mitigation: upgrade to 0.0.31 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-53540 has been found in python-multipart.
Attackers can target a specific entry point like MultipartParser over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 3.7/10.
What to do: upgrade python-multipart to 0.0.31 or later.
If unsure, ask your IT team or search "python-multipart CVE-2026-53540" on the vendor's site.
CVE-2026-53540 (python-multipart) — CWE-1284 / CVSS v3 3.7
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: MultipartParser / http.server / ValueError
Patched: 0.0.31 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-1284) exists in python-multipart. Attackers reach the vulnerable code path via MultipartParser without authentication.
Check the vendor advisory for the affected versions of python-multipart. Attack surface: MultipartParser / http.server / ValueError.
Severity: Low (CVSS 3.7/10). Risk of unauthorized operations or information disclosure.
Update to 0.0.31.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'python-multipart' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'python-multipart' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
python-multipartを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade python-multipart to 0.0.31ステージング環境で 0.0.31 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-53540 python-multipart
- Ubuntu UBUNTU-CVE-2026-53540 python-multipart
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web github.com