CVE-2026-54425

published 2026-10-21

CVE-2026-54425: Uncontrolled recursion in the HTTP/2 HPACK decoder in Apache bRPC before 1.18.0 allows remote attackers to cause denial of service by sending a crafted HTTP/2…

Priority P4 33

Uncontrolled recursion in the HTTP/2 HPACK decoder in Apache bRPC before 1.18.0 allows remote attackers to cause denial of service by sending a crafted HTTP/2 header block containing many consecutive Dynamic Table Size Update entries. Each update was decoded by recursively invoking the HPACK decoder, which could exhaust the thread stack before a header field or end of input was reached.

Root Cause:
The bRPC HPACK decoder recursively decoded the next entry after processing a Dynamic Table Size Update. The decoder did not bound the recursion depth, so a long sequence of update entries could consume excessive stack space.

Affected Scenarios:
Use bRPC with the built-in HTTP/2 implementation to accept HTTP/2 traffic from an untrusted network.

How to Fix:
1. Upgrade bRPC to version 1.18.0, which fixes this issue.
2. Apply this patch: https://github.com/apache/brpc/pull/3343

Note:
The fix changes HPACK Dynamic Table Size Update decoding to use iterative parsing instead of recursive parsing.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
apache_software_foundation	apache_brpc	< 1.18.0	1.18.0

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CWE-674