CVE-2023-42816 | Denial of service from malicious signature in kyverno

Kyverno is a policy engine designed for Kubernetes. A security vulnerability was found in Kyverno where an attacker could cause denial of service of Kyverno. The vulnerability was in Kyvernos Notary verifier. An attacker would need control over the registry from which Kyverno would fetch signatures. With such a position, the attacker could return a malicious response to Kyverno, when Kyverno would send a request to the registry. The malicious response would cause denial of service of Kyverno, such that other users' admission requests would be blocked from being processed. This is a vulnerability in a new component released in v1.11.0. The only users affected by this are those that have been building Kyverno from source at the main branch which is not encouraged. Users consuming official Kyverno releases are not affected. There are no known cases of this vulnerability being exploited in the wild.

Published: 2023-11-13 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-42816 is rated Low Risk (36.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.16%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-42816

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 0.14% 0.16% +0.02%
2 2025-03-29 0.16% 0.14% -0.02%
3 2025-03-19 0.16%

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-42816

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.6 4.0 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.6 3.6 [email protected]

Weakness enumeration for CVE-2023-42816

OS Trackers for CVE-2023-42816

vendor priority summary link
suse medium https://www.suse.com/security/cve/CVE-2023-42816/

Affected software / configurations for CVE-2023-42816

Vendor Product Version Raw CPE
nirmata kyverno 1.11.0 cpe:2.3:a:nirmata:kyverno:1.11.0:-:*:*:*:go:*:*

References for CVE-2023-42816

cvelogic Threat Intelligence