CVE-2026-86146: Apache bRPC · HTTP Request/Response Smuggling
Affects Apache bRPCSource CVE Database V5
Not known to be exploited : upgrade to 1.18.0 soon.
Data as of 26 Oct 2026, 13:47 UTC
Rated High by the CNA (apache) · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.18.0
Exploitation evidence
Disclosed: evidence found.
CVE published 21 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade Apache bRPC and apache/brpc to 1.18.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Apache bRPCapache/brpc | Affected
| Fixed in
|
GitHubapache/brpcpkg:github/apache/brpcOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade Apache bRPC to version 1.18.0, which includes an official fix rejecting problematic header forms and properly handling chunked trailers. Alternatively, apply the patch available at https://github.com/apache/brpc/pull/3521. After upgrading or patching, the default behavior rejects the four problematic header forms and drops chunked trailers instead of merging them. For compatibility, two flags (http_allow_obs_fold=true and http_strict_header_token=true) can be used to restore acceptance of some obsolete header forms if necessary. No other mitigation is required once the fix is applied.
Description
CVE-2026-86146 is a vulnerability in Apache bRPC versions prior to 1.18.0 involving inconsistent interpretation of HTTP/1.1 requests between bRPC and front-end proxies or load balancers. This inconsistency allows remote attackers to perform HTTP request/response smuggling by exploiting differences in header parsing, such as spaces before colons, interior spaces in Content-Length values, obsolete line folding, and chunked trailer handling. The issue can lead to request smuggling, header injection, and response desynchronization. Apache bRPC 1.18.0 fixes this vulnerability by rejecting these problematic header forms and changing how chunked trailers are processed.