Unknown severity · Source severity not reportedCVE-2026-54425

Apache bRPC: Stack Exhaustion via Recursive HPACK Dynamic Table Size Update DecodingCVE-2026-54425

Answer in brief

CVE-2026-54425 records a Unknown severity vulnerability in Apache bRPC: Stack Exhaustion via Recursive HPACK Dynamic Table Size Update Decoding. The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/apache/brpc (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 21, 2026Updated Oct 21, 2026Source checked Oct 21, 2026First seen by HOL Oct 21, 2026Material review Oct 21, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Apache Software Foundation/apache/brpc (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Apache Software Foundation/apache/brpcgeneric	>=0 <1.18.0	1.18.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for Apache Software Foundation/apache/brpc.
Review the reported fix. Update Apache Software Foundation/apache/brpc to 1.18.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 21, 2026

Sources and claim methodology

Source referencelists.apache.org

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.