# CVE-2026-66392: Apache bRPC: TLS Client Accepts Certificates for Mismatched Peer Names


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 21 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-qv5c-vj5j-fg9q

## What is CVE-2026-66392?

CVE-2026-66392 is a vulnerability in Apache bRPC, published on 21 Oct 2026. 

### Official description

Apache bRPC versions before 1.18.0 validate the server certificate chain when client TLS peer verification is enabled, but do not bind the certificate to an expected DNS name or IP address. A network attacker who can redirect or intercept a connection and who possesses a certificate issued by a CA trusted by the client for another name may impersonate the requested TLS endpoint.

Affected Scenarios:
Applications use a bRPC client Channel to connect to an untrusted network with certificate verification enabled and trust a CA that can issue certificates for identities other than the intended endpoint.

How to Fix:
Upgrade to Apache bRPC 1.18.0 and enable VERIFY_PEER with a positive verify_depth. HTTPS Channels automatically verify the certificate against the host in the Channel URL. Callers may set VerifyOptions::expected_peer_name explicitly when the certificate identity differs from the URL host. Alternatively, apply the patch from  https://github.com/apache/brpc/pull/3408 .

Note:
The new option performs DNS SAN or IP SAN verification during the TLS handshake. Configurations that set expected_peer_name while peer verification is disabled are rejected.

Weakness: CWE-297 (Improper Validation of Certificate with Host Mismatch)

## Which versions are affected by CVE-2026-66392?


## How do I fix CVE-2026-66392?

No fix has been published for CVE-2026-66392 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66392 being exploited?

There is no known exploitation of CVE-2026-66392 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66392 and fix it if it is affected.

What it is: CVE-2026-66392 is a vulnerability in Apache bRPC, published on 21 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-66392 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-2026-66392/ (Markdown: https://insights.sbomify.com/CVE-2026-66392/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66392
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66392
- OSV: https://osv.dev/vulnerability/CVE-2026-66392

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66392/
Summaries are generated and may contain mistakes; the official description above is the record.