# Capsule: Malformed ForbiddenAnnotations.Regex can bypass Tenant validation and trigger namespace admission panic

Advisory record · `GHSA-gxjc-74v5-3vx3`

- **Identifiers:** `GHSA-gxjc-74v5-3vx3` · `CVE-2026-61794` · `GO-2026-6521`
- **State:** Confirmed
- **Severity:** CVSS 6.8 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-20](https://cwe.mitre.org/data/definitions/20.html)
- **Tags:** [CWE-20](https://agentprime.io/advisories/tag/cwe-20.md)
- **Published:** 18 Sept 2026
- **Updated:** 28 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 18 Sept 2026, 17:14 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `github.com/projectcapsule/capsule` (Go): affected `>=0.13.0, <0.13.7`; fixed in `0.13.7`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Capsule versions from 0.13.0 before 0.13.7 are affected. A malformed forbidden annotations regex in a Tenant spec can be saved because the webhook validates the forbidden labels regex for both fields. An attacker who can update Tenant configuration can then cause namespace admission failures for that tenant, a tenant-scoped denial of service. Upgrade to Capsule 0.13.7 or later.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 6.8 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0059, the 48th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:12 UTC: First seen by agentprime
- 31 Oct 2026, 14:12 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-gxjc-74v5-3vx3)

## Sources

- [GitHub Advisory Database: GHSA-gxjc-74v5-3vx3](https://github.com/advisories/GHSA-gxjc-74v5-3vx3)
- [OSV: GHSA-gxjc-74v5-3vx3](https://osv.dev/vulnerability/GHSA-gxjc-74v5-3vx3)
- <https://github.com/projectcapsule/capsule/security/advisories/GHSA-gxjc-74v5-3vx3>
- <https://github.com/projectcapsule/capsule/pull/1983>
- <https://github.com/projectcapsule/capsule/commit/8d89d6865df6f41c7faa22fc9e807a57b01bfd0e>
- <https://github.com/projectcapsule/capsule>
- <https://github.com/projectcapsule/capsule/releases/tag/v0.13.7>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-gxjc-74v5-3vx3>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-gxjc-74v5-3vx3/>. Everything for agents: <https://agentprime.io/llms.txt>.