CVE-2026-54340 | BDVDB-2026-348982 Detail

Description#

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 9265bdd, there is an HTTP/2 state amplification issue that combines HPACK decompression amplification with Slowloris-style stream stalling. Amplified decoded header state can be retained by stalled HTTP/2 streams, and depending on the configuration, additional limits are needed to bound decoded header state and prevent attack. This issue has been fixed by commit 9265bdd.

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Exploit#

History#

1. Version 12026-07-16Record published in the CVE List.
2. Version 22026-07-17Most recent update recorded in the CVE List.