# CVE-2026-122303: Kyverno 1.17.0 before 1.19.2 Cross-Namespace Resource Overwrite via NamespacedMutatingPolicy


- **Severity:** Critical 9.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 5 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-jcw5-3wcg-fqx5, GHSA-m6w5-f9j8-9pjp

## What is CVE-2026-122303?

CVE-2026-122303 is a critical vulnerability in kyverno, published on 5 Nov 2026. 

### Official description

Kyverno from 1.17.0 before 1.19.2 contains an authorization bypass vulnerability that allows namespace tenants to overwrite resources in other namespaces via NamespacedMutatingPolicy mutate-existing targetMatchConstraints.expression. Attackers can return a CEL map literal fabricating a target with an attacker-chosen metadata.namespace, causing the privileged background controller to overwrite Secrets, Deployments, or policies cluster-wide.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2026-122303?

It affects 1 product.


Products: Kyverno.

## How do I fix CVE-2026-122303?

No fix has been published for CVE-2026-122303 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-122303 being exploited?

There is no known exploitation of CVE-2026-122303 in the wild and no public exploit code.

## Other vulnerabilities in kyverno

- [CVE-2026-22039](https://insights.sbomify.com/CVE-2026-22039/): Kyverno Cross-Namespace Privilege Escalation via Policy apiCall (critical 10.0)
- [CVE-2026-4789](https://insights.sbomify.com/CVE-2026-4789/): CVE-2026-4789 (critical 9.8)
- [CVE-2026-122304](https://insights.sbomify.com/CVE-2026-122304/): Kyverno 1.17.0 before 1.19.2 Privilege Escalation via CleanupPolicy Context Loader (critical 9.4)
- [CVE-2026-122310](https://insights.sbomify.com/CVE-2026-122310/): Kyverno 1.19.1 before 1.19.2 Privilege Escalation via Policy apiCall urlPath (critical 9.4)
- [CVE-2026-122311](https://insights.sbomify.com/CVE-2026-122311/): Kyverno 1.16.0 before 1.19.2 Path Traversal in Namespaced CEL Policies via resource argument (critical 9.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-122303 and fix it if it is affected.

What it is: CVE-2026-122303 is a critical vulnerability in kyverno, published on 5 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-122303 in the wild and no public exploit code.

Affected product: kyverno. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-122303/ (Markdown: https://insights.sbomify.com/CVE-2026-122303/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-122303
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-122303
- OSV: https://osv.dev/vulnerability/CVE-2026-122303

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-122303/
Summaries are generated and may contain mistakes; the official description above is the record.