CRLF injection in aiohttp - CVE-2026-34514
Published: April 26, 2026
Vulnerability identifier: #VU127953
CSH Severity: Medium
CVSS v4.0: 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/U:Green
CVE-ID: CVE-2026-34514
CWE-ID: CWE-93
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: aio-libs
Affected software:
aiohttp
aiohttp
Detailed vulnerability description
The vulnerability allows a remote attacker to inject extra headers into a multipart request.
The vulnerability exists due to improper neutralization of carriage return and line feed characters in multipart part content type header construction when constructing a multipart request with an attacker-controlled content_type parameter. A remote attacker can supply a crafted content_type value to inject extra headers into a multipart request.
The issue occurs if an application uses untrusted data for the multipart content_type parameter while constructing a request.
How to mitigate CVE-2026-34514
Install security update from vendor's website.