Vulnerability · Published Oct 21, 2026 · Assigned by apache
CVE-2026-54425Apache bRPC: Stack Exhaustion via Recursive HPACK Dynamic Table Size Update Decoding
High 7.5
In plain English
A high-severity security flaw in Apache bRPC from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 51% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache bRPC | 0 – before 1.18.0 |
Weakness: CWE-674 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb vendor-advisory