AIOHTTP has HTTP response splitting via \r in reason phrase
### Summary An attacker who controls the `reason` parameter when creating a `Response` may be able to inject extra headers or similar exploits. ### Impact In the unlikely situation that an application allows untrusted data to be used in the response's `reason` parameter, then an attacker could manipulate the response to send something different from what the developer intended. ----- Patch: https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2b
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-34519US | medium5.3 | — | ||
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the reason parameter when creating a Response may… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/aio-libs/aiohttpPACKAGE
- https://github.com/aio-libs/aiohttp/commit/53b35a2f8869c37a133e60bf1a82a1c01642ba2bWEB
- https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4WEB
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mwh4-6h8g-pg8wWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-34519ADVISORY
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