CVE-2026-126367: Auth Bypass (CVSS 4.8)

Description

@grpc/grpc-js implements the core functionality of gRPC purely in JavaScript, without a C++ addon. Before 1.13.2, and from 1.14.0 through 1.14.1, the @grpc/grpc-js-xds SafeRegexValueMatcher and PathSafeRegexValueMatcher add start and end anchors without grouping a supplied top-level alternation. An expression intended to match one of several complete values can therefore match a prefix, substring, or suffix. The affected matchers are used for route selection, xDS credential identity matching, and RBAC URL path, principal name, server name, and header rules. An ALLOW policy using an alternation can consequently accept a method, certificate identity, or header value outside the intended set, while a DENY policy becomes broader rather than permissive. This issue is fixed in versions 1.13.2 and 1.14.2.

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CVSS v3.1 Score

4.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Weakness Type (CWE)

CWE-625 CWE-625

CWE-863 Incorrect Authorization

References

Other References

https://github.com/grpc/grpc-node/commit/3fc3b0ebf7a89d64843a73679951142d33b40cb1 https://github.com/grpc/grpc-node/commit/57a67e96babcb29b6eabc1833221ccf2fa152d43 https://github.com/grpc/grpc-node/releases/tag/@grpc/[email protected] https://github.com/grpc/grpc-node/releases/tag/@grpc/[email protected] https://github.com/grpc/grpc-node/security/advisories/GHSA-r7hq-q2xm-6c5m

Frequently Asked Questions

What is CVE-2026-126367? +

@grpc/grpc-js implements the core functionality of gRPC purely in JavaScript, without a C++ addon. Before 1.13.2, and from 1.14.0 through 1.14.1, the @grpc/grpc-js-xds SafeRegexValueMatcher and PathSafeRegexValueMatcher add start and end anchors without grouping a supplied top-level alternation. An expression intended to match one of several complete values can therefore match a prefix, substring, or suffix. The affected matchers are used for route selection, xDS credential identity matching, and RBAC URL path, principal name, server name, and header rules. An ALLOW policy using an alternation can consequently accept a method, certificate identity, or header value outside the intended set, while a DENY policy becomes broader rather than permissive. This issue is fixed in versions 1.13.2 and 1.14.2. It has a CVSS v3.1 base score of 4.8 (MEDIUM).

How severe is CVE-2026-126367? +

CVE-2026-126367 has a CVSS v3.1 score of 4.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2026-126367? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-126367