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CVE-2026-42530 – Nginx HTTP3/QUIC Use-After-Free

my.f5.com
7 pointskro4 comments
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I mentioned this in a previous post for this CVE. How much heavy lifting is the phrase "along with conditions beyond their control" doing for this exploit?

When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially crafted HTTP/3 session to reopen a QPACK encoder stream.
kroOP

These commits [1] are related to the issue. I am not too familiar with the code, but it appears nginx manages/closes streams in a pool at times the attacker cannot control, and during short windows, it is vulnerable.

[1]:

https://github.com/nginx/nginx/commit/ceccdbd2ee799d020a371b...

https://github.com/nginx/nginx/commit/9e293766e73c469c015df5...

kroOP

Only 1.31.0 and 1.31.1 are affected.

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