---
id: "CVE-2026-89314"
kind: "vulnerability"
aliases: ["CVE-2026-89314"]
title: "JWK library: quadratic key_ops check lets a crafted JWKS stall CPU"
severity: "medium"
cvss: 6.9
epss: 0.00253
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["go-or-library-unknown", "jwk", "jwks", "package", "self-hosted"]
not_affected_if: ["trusted-key-sources-only"]
published_at: "2026-10-23T09:17:07+00:00"
first_seen_at: "2026-10-23T21:57:32+00:00"
updated_at: "2026-10-25T03:38:36+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89314", "first_seen_at": "2026-10-23T21:57:32+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-89314", "first_seen_at": "2026-10-24T07:15:51+00:00"}]
---

# JWK library: quadratic key_ops check lets a crafted JWKS stall CPU

The JWK parser checks for duplicate key_ops entries with a nested loop, so validation time grows with the square of the entry count. A hostile JWKS document with many key_ops values can keep a CPU core busy for many seconds on every unmarshal.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- unknown

## Timeline

- 2026-10-23T21:57:32+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-89314
- 2026-10-24T07:15:51+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-89314

## From the sources

`jwkFields.CheckConsistency` detected duplicate `key_ops` entries with a pairwise nested loop, making validation cost grow with the **square** of the entry count. Because the check runs on every JWK and JWKS unmarshal, a modestly sized but hostile JWKS document could occupy a CPU core for many seconds.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_