CVE-2026-122318: kyverno Cert Validation Flaw — Exploit

Description

Kyverno before 1.19.2 contains an authentication bypass in matchCertificateData that skips verifyImages subject and subjectRegExp checks when the signing certificate has no Subject Alternative Name. Attackers holding a leaf certificate from a configured private trust root can omit the SAN, set the expected Fulcio issuer OID, and sign malicious images that are admitted despite signer pinning.

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CVSS v3.1 Score

7.7

HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:L

EPSS — Exploit Prediction

0.0017

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

Affected Products

Vendor	Product	Versions
kyverno	kyverno	< 1.19.2

References

Frequently Asked Questions

What is CVE-2026-122318? +

Kyverno before 1.19.2 contains an authentication bypass in matchCertificateData that skips verifyImages subject and subjectRegExp checks when the signing certificate has no Subject Alternative Name. Attackers holding a leaf certificate from a configured private trust root can omit the SAN, set the expected Fulcio issuer OID, and sign malicious images that are admitted despite signer pinning. It has a CVSS v3.1 base score of 7.7 (HIGH).

How severe is CVE-2026-122318? +

CVE-2026-122318 has a CVSS v3.1 score of 7.7 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0017, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-122318? +

CVE-2026-122318 affects products from kyverno, specifically: kyverno. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-122318? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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