CVE-2026-50269
aiohttp: CRLF injection in multipart headers
Description
### 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
How to fix CVE-2026-50269
To remediate CVE-2026-50269, upgrade the affected package to a fixed version below.
- PyPI/aiohttp—upgrade to 3.14.0 or later
Is CVE-2026-50269 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-50269.
Affected packages (1)
- from 0, < 3.14.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U |