Kyverno before 1.19.2 Denial of Service via Exponential-Time Wildcard Matching
Kyverno versions before 1.19.2 are affected, and the fix is in Kyverno 1.19.2. The vulnerability is a denial of service of the Kyverno admission controller.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 1.19.2
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Kyverno versions before 1.19.2 are affected
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.30% · 22nd percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 16/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Kyverno, a Kubernetes policy engine, is affected by a denial-of-service flaw in which a user with low-privilege access to create namespaced policies can submit crafted wildcard patterns that exhaust the admission controller's CPU. This can be triggered remotely, after logging in with low privileges, and can cause cluster-wide webhook timeouts that block resource operations.
Read the original description
Kyverno before 1.19.2 contains a denial of service vulnerability that allows namespaced policy authors to exhaust admission controller CPU by submitting pathological wildcard patterns. Attackers can create a Policy with crafted match and exclude names evaluated by ValidateMatchExcludeConflict, pinning cores and causing cluster-wide webhook timeouts that block resource operations.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.3/10CVSS 8.3
- No patch0/5No signal
What would change the score
- Would score about 66 if added to CISA KEV
- Would score about 61 if CISA's SSVC rates exploitation active
- Would score about 23 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Kyverno versions before 1.19.2 are affectedUpgrade to a fixed version: 1.19.2.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- kyverno kyverno
fixed in 1.19.2
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-122306
Is CVE-2026-122306 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: cve.now feed data
What does this mean?
A user permitted to author a namespaced Kyverno Policy can trigger exponential-time wildcard matching in the admission controller. This exhausts CPU, so cluster-wide webhooks time out and block resource operations.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-122306?
kyverno: before 1.19.2.Source: cve.now feed data
Am I affected, and how do I check?
All Kyverno versions before 1.19.2 are affected. To check, run the Kyverno version command or inspect the version of the Kyverno admission controller image in the cluster.Source: vulncheck.com, github.com
How do I fix CVE-2026-122306?
Upgrade Kyverno to 1.19.2 or later, which contains the fix.Source: vulncheck.com, github.com