CVE-2026-54425
Apache bRPC: Stack Exhaustion via Recursive HPACK Dynamic Table Size Update Decoding
- State
- Published
- Severity
- 7.5 High
- Published
- Oct 21, 2026
- Updated
- Oct 30, 2026
- Reserved
- Jun 14, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CISA-ADP |
Weaknesses
- CWE-674 Uncontrolled Recursion
Affected Products
| Product | Versions |
|---|---|
Apache bRPCApache Software Foundation |
|
References
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