---
id: "CVE-2026-122323"
kind: "vulnerability"
aliases: ["CVE-2026-122323"]
title: "Kyverno: unbounded decompression in signature fetch lets attackers crash admission controller"
severity: "high"
cvss: 8.7
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["admission-controller", "infrastructure", "kubernetes", "kyverno"]
not_affected_if: ["fixed-version", "no-verifyimages-rules"]
published_at: "2026-11-05T03:17:25+00:00"
first_seen_at: "2026-11-05T03:31:42+00:00"
updated_at: "2026-11-05T03:33:11+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-122323", "first_seen_at": "2026-11-05T03:31:42+00:00"}]
exploit_sources: []
---

# Kyverno: unbounded decompression in signature fetch lets attackers crash admission controller

Kyverno versions from 1.11.0 before 1.19.2 decompress notary signature layers without a size limit in FetchSignatureBlob. An attacker who controls registry signatures can publish small gzip layers that expand past the maximum payload size, exhausting memory and causing the admission controller to be OOM-killed.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Kyverno version running in the cluster, e.g. `kubectl get deploy -n kyverno -o jsonpath='{.items[*].spec.template.spec.containers[*].image}'`
- Confirm whether the image tag is at or above `1.19.2` and below `1.11.0` is not in use
- Check whether Kyverno verifies image signatures from registries that untrusted parties can write to (verifyImages rules)

## Fix

- Kyverno: upgrade to `1.19.2` or later

## Timeline

- 2026-11-05T03:31:42+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-122323

## Documents

- [advisory] Vendor advisory: github.com https://github.com/kyverno/kyverno/security/advisories/GHSA-fr24-3hvf-393q
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/kyverno-1.11.0-before-1.19.2-memory-exhaustion-via-notary-signature-decompression

## From the sources

Kyverno from 1.11.0 before 1.19.2 contains an unbounded decompression vulnerability in FetchSignatureBlob that allows attackers to exhaust memory by supplying highly compressed notary signature layers. Attackers who control registry referrers or signatures can publish small gzip layers that decompress beyond maxPayloadSize, causing admission controller OOM kills and denial of service.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_