# CVE-2026-86146: Apache bRPC HTTP request/response smuggling in bundled parser

Source: https://junglewise.ai/threats/cve-2026-86146-inconsistent-interpretation-of-http-requests-http-request  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-86146 · Severity: info · Published 2026-10-21

Apache bRPC is a high-performance RPC framework used to build distributed services. When deployed behind a proxy or load balancer, its HTTP/1.1 parser interprets malformed headers differently than standard parsers, allowing attackers to inject false headers (like authorization credentials), forge forwarding information, or desynchronize request/response framing between the proxy and bRPC. This can lead to request smuggling, header injection, and bypassing proxy-level security controls.

Technologies: [Apache Brpc](https://junglewise.ai/threats/technologies/brpc). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-86146 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86146 being exploited in the wild.

**How severe is CVE-2026-86146?** Informational severity, published 21 October 2026.

**Which products and versions are affected?** Apache Brpc < 1.18.0.

**Is there a fix for CVE-2026-86146?** Yes: fixed in 1.18.0. Until then: Apply the patch from https://github.com/apache/brpc/pull/3521 if immediate upgrade is not possible. After patching, the non-conformant header forms are rejected by default; use gflags http_allow_obs_fold=true or http_strict_header_token=true only if legacy clients require the obsolete forms. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86146 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-86146?** Check whether you run Apache Brpc at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.18.0

Apply the patch from https://github.com/apache/brpc/pull/3521 if immediate upgrade is not possible. After patching, the non-conformant header forms are rejected by default; use gflags http_allow_obs_fold=true or http_strict_header_token=true only if legacy clients require the obsolete forms.

## Technical details

The bRPC HTTP/1.1 parser accepts five classes of non-conformant HTTP/1.1 syntax: spaces before header colons, interior spaces in Content-Length values, obsolete line folding in framing headers, chunked trailer fields merged into the header map, and Transfer-Encoding lists with optional whitespace after commas. These inconsistencies allow an attacker to craft requests that parse differently at a front-end proxy versus bRPC, enabling request smuggling, header injection (Authorization, X-Forwarded-For), and response desynchronization. The vulnerability affects any bRPC deployment communicating over HTTP/1.1 with independent parsers such as proxies or load balancers.

## Affected products

- Apache bRPC < 1.18.0

## Timeline

- 2026-10-21: disclosed

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