High priorityDisclosed

Advisory · CVE-2026-122319

Kyverno In and NotIn operators can panic the policy engine

Kyverno before 1.19.2 has a denial-of-service flaw in the In and NotIn operators: an unchecked type assertion lets attackers crash the policy engine with resources whose JMESPath-evaluated values yield arrays of integers, booleans, or mixed types. Kyverno rates it CVSS 4.0 8.7.

Advisory published November 5, 2026Independent summary
Vendor
Kyverno
Product
Kyverno
Identifier / CWE
CVE-2026-122319
CWE-704
Action timing
Immediate
ELI5

Explain it like I’m five

A policy rule that compares lists assumes the list holds text. Hand it numbers or booleans and the engine crashes, taking admission control down with it.

SIMPLIFIED_ATTACK_PATH04 STEPS
  1. 01Crafted resource submitted

    An attacker submits a resource whose JMESPath-evaluated values yield arrays of integers, booleans, or mixed types.

  2. 02In or NotIn evaluated

    A policy using the In or NotIn operator evaluates the crafted values.

  3. 03Type assertion panics

    The unchecked type assertion crashes the policy engine.

  4. 04Admission disrupted

    The panic disrupts admission control and policy enforcement.

What happened

Kyverno disclosed CVE-2026-122319 for Kyverno before 1.19.2. The In and NotIn operators contain a denial-of-service vulnerability: an unchecked type assertion lets attackers crash the policy engine by submitting resources whose JMESPath-evaluated values yield arrays of integers, booleans, or mixed types, triggering a panic that disrupts admission control and policy enforcement.

The advisory rates it CVSS 4.0 8.7 and identifies Kyverno 1.19.2 as the fixed release.

What to do

  1. Inventory Kyverno installations and confirm the deployed version.
  2. Upgrade affected installations to Kyverno 1.19.2 or later using the project release guidance.
  3. Watch admission webhook health and logs for policy engine panics.
  4. Review resources admitted during any webhook outage for policy violations.
  5. Audit policies using In and NotIn operators against non-string fields.

Management note

Any user who can submit a resource can trigger this one, so the bar to attack is as low as it gets. A crash in the admission path is a cluster-wide event even when the trigger is a single odd resource.