Improper validation of certificate with host mismatch in Apache bRPC - CVE-2026-66392
Published: October 23, 2026
Vulnerability identifier: #VU157346
CSH Severity: Medium
CVSS v4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-66392
CWE-ID: CWE-297
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to impersonate the TLS endpoint requested by a bRPC client.
The vulnerability exists due to improper certificate hostname validation in Apache bRPC's TLS client when peer verification validates a certificate chain without checking the expected DNS name or IP address. A remote attacker can redirect or intercept a connection and present a certificate for another identity issued by a CA trusted by the client to impersonate the intended endpoint.
Affected software
Apache bRPC
How to mitigate CVE-2026-66392
Install security update from vendor's website.
Apache bRPC - update to 1.18.0