IA Squad
SearchPT
python · aiohttpHeads-up

aiohttp: TLS SNI check bypass when reusing connection with different server_hostname

A vulnerability in aiohttp allows bypass of the TLS SNI check when reusing an existing connection with different per-request server_hostname parameters.

16 Jun 2026Read 1 minSeverity: schedule it

What changed

A vulnerability in aiohttp allows bypass of the TLS SNI check when reusing an existing connection with different per-request server_hostname parameters.

Who it affects

Applications using aiohttp that make multiple requests to the same domain with different server_hostname values.

What to do today

Apply the patch from commit 0ca2b6c28a25726527a8b60f25960262a91ed0e0 or disable keep_alive if changing server_hostname between requests.

The trail
Collected Audited Written Published