Cyber Resilience

CVE-2026-4789

SSRF in Kyverno 1.16.0 – 1.17.1

Published
30 March 2026
Modified
03 April 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0070 50th percentile
Risk Priority 72 floored blend · peak EPSS

Summary

CVE-2026-4789 is a critical-severity SSRF (CWE-918) vulnerability in Kyverno Kyverno. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 50th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-4789 is a Server-Side Request Forgery (SSRF) vulnerability, classified under CWE-918, affecting Kyverno versions 1.16.0 and later due to unrestricted CEL HTTP functions. Published on 2026-03-30, it carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity with network accessibility, low attack complexity, no privileges or user interaction required, and high impacts on confidentiality, integrity, and availability.

Unauthenticated remote attackers can exploit this vulnerability over the network. By leveraging the unrestricted CEL HTTP functions, they can induce Kyverno to make unintended requests, potentially accessing internal resources, bypassing network restrictions, or interacting with external services in ways that lead to significant compromise.

Advisories and further details are available in referenced sources, including the Kyverno GitHub repository at https://github.com/kyverno/kyverno, CERT KB entry at https://kb.cert.org/vuls/id/655822, and general SSRF guidance at https://portswigger.net/web-security/ssrf.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Kyverno, versions 1.16.0 and later, are vulnerable to SSRF due to unrestricted CEL HTTP functions.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-22039Same product: Kyverno Kyverno
CVE-2026-41323Same product: Kyverno Kyverno
CVE-2025-46342Same product: Kyverno Kyverno
CVE-2025-47281Same product: Kyverno Kyverno
CVE-2026-41068Same product: Kyverno Kyverno
CVE-2025-29778Same product: Kyverno Kyverno
CVE-2026-23881Same product: Kyverno Kyverno
CVE-2026-40868Same product: Kyverno Kyverno
CVE-2026-41485Same product: Kyverno Kyverno
CVE-2023-47630Same product: Kyverno Kyverno

Affected Assets

kyverno
kyverno
1.16.0 — 1.17.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.3.6
  • V1.5.3
  • V5.3.2
  • V10.4.7

Mitigating Controls (NIST 800-53 r5) AI

Information flow enforcement can restrict which destinations the server is allowed to contact on behalf of users.

Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.

Boundary protection limits the network reach of server-initiated requests even if SSRF occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

References