# CVE-2026-61916: Apache bRPC: Out-of-bounds Read in URL and Header Lookup Tables on Unsigned-char Platforms


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 21 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-7g7p-w25v-9p63

## What is CVE-2026-61916?

CVE-2026-61916 is a vulnerability in Apache bRPC, published on 21 Oct 2026. 

### Official description

Out-of-bounds reads in URL parsing and case-insensitive header lookup in Apache bRPC before version 1.18.0 on platforms where plain char is unsigned, such as ARM64, allow remote attackers to cause a process crash and denial of service by sending crafted input containing bytes with the high bit set.

Root Cause:
Two 256-entry lookup tables are accessed through pointers biased by 128 so that valid indices are in the range -128 to 127. Input bytes are promoted from plain char to int without first normalizing them to the signed-char range. On affected platforms, bytes in the range 0x80 to 0xFF therefore become indices 128 to 255 and read up to 127 bytes beyond the end of the underlying tables.

Affected Scenarios:
A remotely accessible bRPC HTTP server on an affected platform can reach the vulnerable URL lookup through an unauthenticated request URI containing a high-bit byte. The case-insensitive lookup is also reachable when untrusted header names are processed through APIs such as the HTTP/2 HPACK path. HTTP/1 header names containing high-bit bytes are rejected by the HTTP/1 parser before reaching the vulnerable lookup. Builds where plain char is signed, which commonly include x86_64 builds, are not affected by this issue.

How to Fix:
Choose one of the following options:
1. Upgrade Apache bRPC to version 1.18.0 or later.
2. Apply the patch from  https://github.com/apache/brpc/pull/3376 .

The fix normalizes lookup-table indices to the signed-char range before accessing the biased tables.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-61916?


## How do I fix CVE-2026-61916?

No fix has been published for CVE-2026-61916 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-61916 being exploited?

There is no known exploitation of CVE-2026-61916 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-61916 and fix it if it is affected.

What it is: CVE-2026-61916 is a vulnerability in Apache bRPC, published on 21 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-61916 in the wild and no public exploit code.

Affected product: Apache bRPC. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-61916/ (Markdown: https://insights.sbomify.com/CVE-2026-61916/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-61916
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-61916
- OSV: https://osv.dev/vulnerability/CVE-2026-61916

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-61916/
Summaries are generated and may contain mistakes; the official description above is the record.