Vulnerability in aiohttp (CVE-2026-50269)
Summary
Vulnerability in aiohttp (CVE-2026-50269). Risk of unauthorized operations or information disclosure. Exploitable via Payload.headers. Mitigation: upgrade to 3.14.0 or later.
Original description
The description as published by the source.
Summary
Attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar.
Impact
In the unlikely situation that an application is passing user-controlled strings into MultipartWriter.append(headers=...) or Payload.headers, then an attacker may be able to modify the request to inject headers or change the contents of the request.
Workaround
Sanitise such user input.
Patch: https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8
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-2026-50269 has been found in aiohttp.
Attackers can target a specific entry point like Payload.headers over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade aiohttp to 3.14.0 or later.
If unsure, ask your IT team or search "aiohttp CVE-2026-50269" on the vendor's site.
CVE-2026-50269 (aiohttp) — CWE-93 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Payload.headers
Patched: 3.14.0 — 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-93) exists in aiohttp. Attackers reach the vulnerable code path via Payload.headers without authentication.
Check the vendor advisory for the affected versions of aiohttp. Attack surface: Payload.headers.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 3.14.0.
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 'aiohttp' . 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 'aiohttp' . | 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
aiohttp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 aiohttp to 3.14.0ステージング環境で 3.14.0 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-2026-50269 python-aiohttp
- Ubuntu UBUNTU-CVE-2026-50269 python-aiohttp
References
- advisory security-advisories@github.com
- patch security-advisories@github.com
- web github.com