How severe is GHSA-3vcp-chfh-f6r2?

No CVSS score has been assigned to GHSA-3vcp-chfh-f6r2 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-3vcp-chfh-f6r2?

GHSA-3vcp-chfh-f6r2 affects the following packages: github.com/kumahq/kuma (Go), github.com/kumahq/kuma (Go), github.com/kumahq/kuma (Go), github.com/kumahq/kuma (Go), github.com/kumahq/kuma (Go). Ecosystems affected: Go.

How do I fix GHSA-3vcp-chfh-f6r2?

Update github.com/kumahq/kuma to 2.7.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3vcp-chfh-f6r2 is resolved across your whole dependency graph.

How do I detect GHSA-3vcp-chfh-f6r2 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/kumahq/kuma. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-3vcp-chfh-f6r2 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-3vcp-chfh-f6r2?

O3 pinpoints whether GHSA-3vcp-chfh-f6r2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-3vcp-chfh-f6r2 actively exploited in the wild?

No public exploit code has been indexed for GHSA-3vcp-chfh-f6r2 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-3vcp-chfh-f6r2?

GHSA-3vcp-chfh-f6r2 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 10th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-3vcp-chfh-f6r2?

GHSA-3vcp-chfh-f6r2 is classified as CWE-346 (CWE-346), CWE-942 (CWE-942). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-3vcp-chfh-f6r2 published, and has it been updated?

GHSA-3vcp-chfh-f6r2 was published on May 14, 2026 and was last updated on August 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

GHSA-3vcp-chfh-f6r2

Fix: kumahq/kuma#16416

GHSA-3vcp-chfh-f6r2 is a CWE-346 vulnerability in github.com/kumahq/kuma. O3 Security confirms whether GHSA-3vcp-chfh-f6r2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Default kuma-cp leaks admin token cross-origin via CORS wildcard + LocalhostIsAdmin

Also known asCVE-2026-45021GO-2026-5102

Published

May 14, 2026

Updated

Aug 8, 2026

Affected

5 pkgs

Patched

5 / 5

Exploits

None indexed

Exploitation data as of Aug 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-3vcp-chfh-f6r2.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs10th percentile — riskier than 10% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

5 pkgs affected

🐹github.com/kumahq/kuma🐹github.com/kumahq/kuma🐹github.com/kumahq/kuma🐹github.com/kumahq/kuma🐹github.com/kumahq/kuma

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

Default kuma-cp config leaks the admin bootstrap token and signing keys to any webpage the operator visits while the control plane is reachable from their browser. CorsAllowedDomains: [".*"] reflects any Origin, and LocalhostIsAdmin: true promotes requests from 127.0.0.1 to mesh-system:admin. A cross-origin fetch() from a malicious page returns the admin JWT and signing material.

Am I affected?

You are affected if all of these hold:

kuma-cp runs with default config (CorsAllowedDomains: [".*"] and LocalhostIsAdmin: true).
The control plane is reachable from a browser on the same machine:
- kuma-cp run on a developer laptop
- Docker --network host or port-publish on a workstation
- kubectl port-forward from a machine that also browses the web
The operator visits a page running attacker JavaScript while the control plane is reachable.

You are not affected if:

The control plane runs on a Kubernetes cluster accessed via ClusterIP, NodePort, or LoadBalancer from a remote client.
The control plane runs on an SSH-administered VM with no browser on the host.
KUMA_API_SERVER_AUTHN_LOCALHOST_IS_ADMIN=false is set (see https://kuma.io/docs/latest/production/secure-deployment/api-server-auth/).
KUMA_API_SERVER_CORS_ALLOWED_DOMAINS is set to an explicit allowlist that excludes attacker origins.

Mitigation

Set KUMA_API_SERVER_AUTHN_LOCALHOST_IS_ADMIN=false after retrieving the admin token.
Set KUMA_API_SERVER_CORS_ALLOWED_DOMAINS to an explicit allowlist, for example http://localhost:5681,http://127.0.0.1:5681.
Do not run kuma-cp on a machine where you browse untrusted sites.

Fix

Fixed in #16416, backported to all supported release branches (#16423, #16424, #16425, #16426, #16427).

Changes in patched versions:

CorsAllowedDomains default changed from [".*"] to [] — CORS is now opt-in; set the env var explicitly if you need GUI access.
LocalhostIsAdmin hardened: now requires direct loopback RemoteAddr and Host, and rejects requests carrying proxy-hop headers (X-Forwarded-For), cross-site fetch metadata (Sec-Fetch-Site), or a non-localhost Origin.

Upgrade to a patched version:

2.7.25
2.9.15
2.11.13
2.12.10
2.13.5

Credits

Reported by eldudareeno.

CVSS

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N = 5.1 Medium.

Affected Packages

5 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/kumahq/kuma`	all versions	2.7.25
🐹Go	`github.com/kumahq/kuma`	≥ 2.9.0&&< 2.9.15	2.9.15
🐹Go	`github.com/kumahq/kuma`	≥ 2.11.0&&< 2.11.13	2.11.13
🐹Go	`github.com/kumahq/kuma`	≥ 2.12.0&&< 2.12.10	2.12.10
🐹Go	`github.com/kumahq/kuma`	≥ 2.13.0&&< 2.13.5	2.13.5

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/kumahq/kuma. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/kumahq/kuma to 2.7.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3vcp-chfh-f6r2 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-3vcp-chfh-f6r2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-3vcp-chfh-f6r2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary Default `kuma-cp` config leaks the admin bootstrap token and signing keys to any webpage the operator visits while the control plane is reachable from their browser. `CorsAllowedDomains: [".*"]` reflects any `Origin`, and `LocalhostIsAdmin: true` promotes requests from `127.0.0.1` to `mesh-system:admin`. A cross-origin `fetch()` from a malicious page returns the admin JWT and signing material. ## Am I affected? You are affected if all of these hold: 1. `kuma-cp` runs with default config (`CorsAllowedDomains: [".*"]` and `LocalhostIsAdmin: true`). 2. The control plane is reachabl

O3 Security · Impact-Aware SCA

Is GHSA-3vcp-chfh-f6r2 in your dependencies?

O3 detects GHSA-3vcp-chfh-f6r2 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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