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CVE-2026-66392

Apache bRPC: TLS Client Accepts Certificates for Mismatched Peer Names

5.9 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
None

Exploit likelihood

0.21%Up 0.1 points since Oct 22, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.9

Apache bRPC: TLS Client Accepts Certificates for Mismatched Peer Names

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.

Record
CVE-2026-66392
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-297
Updated
2026-11-02
EUVDEUVD-2026-107178 5.9

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.

Record
EUVD-2026-107178
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-qv5c-vj5j-fg9q 5.9

Apache bRPC versions before 1.18.0 validate the server certificate chain when client TLS peer...

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.

Record
GHSA-qv5c-vj5j-fg9q
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-297
Updated
2026-11-02
NVD 5.9

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.

Record
CVE-2026-66392
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-297
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-66392 is a medium vulnerability (CVSS 5.9) in Apache Software Foundation Brpc, published October 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 10th percentile. No source names a fixed version.

References

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