# 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.

Source: https://junglewise.ai/threats/cve-2026-126367-grpc-grpc-js-safe-regex-incorrectly-applies-partial-string  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-13. Updated: 2026-11-12  
License: CC BY 4.0 with a link back

CVE-2026-126367 · Severity: medium · CVSS 4.8 · Published 2026-11-13

The gRPC JavaScript library incorrectly evaluates regex patterns used for access control in route selection, credential validation, and RBAC rules. When a pattern uses alternation (e.g., "path1|path2"), the regex anchors bind incorrectly, allowing partial string matches instead of requiring exact matches. An attacker can bypass ALLOW policies and access restricted methods, services, or resources not explicitly granted.

Technologies: [@grpc/grpc-js-xds (npm)](https://junglewise.ai/threats/technologies/grpc-grpc-js-xds). Vendors: [Grpc](https://junglewise.ai/threats/vendors/grpc), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-126367 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-126367 being exploited in the wild.

**How severe is CVE-2026-126367?** Medium severity, with a CVSS score of 4.8, published 13 November 2026.

**Which products and versions are affected?** @grpc/grpc-js-xds (npm) >= 1.14.0, < 1.14.2, SEMVER:introduced=1.14.0,fixed=1.14.2.

**Is there a fix for CVE-2026-126367?** Yes. @grpc/grpc-js-xds (npm): upgrade to 1.14.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-126367 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-126367?** Check whether you run Grpc-Js-Xds or @grpc/grpc-js-xds (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- @grpc/grpc-js-xds (npm): upgrade to 1.14.2 or later

  ```sh
  npm install @grpc/grpc-js-xds@1.14.2
  ```


## Technical details

The SafeRegexValueMatcher constructs regex as `^${regex}$` without wrapping alternations in a non-capturing group, causing top-level alternation operators to bind anchors only to the first and last branches. This results in partial matching semantics (e.g., `^a|b|c$` matches "starts with a" OR "contains b" OR "ends with c" rather than full string match). The vulnerability affects route selection, xDS credential SAN matching, and RBAC url_path permissions and principals, allowing policy bypass via crafted method or service identities.

## Affected products

- gRPC grpc-js-xds

## Identifiers

- CVE-2026-126367
- GHSA-r7hq-q2xm-6c5m

## Timeline

- 2026-11-12: disclosed

## Related threats

- [grpc-js-xds RBAC override policy bypass](https://junglewise.ai/threats/cve-2026-128065-grpc-grpc-js-rbac-override-configs-in-virtualhost-and-route)
- [gRPC grpc-js incorrect authorization in RBAC path matching](https://junglewise.ai/threats/cve-2026-101914-grpc-grpc-js-the-exact-path-match-matcher-incorrectly-only)