---
title: "CVE-2025-59936: get-jwks: poisoned JWKS cache allows post-fetch issuer validation bypass"
url: https://erroneo.us/security/cve/CVE-2025-59936/
description: "CVE-2025-59936 (get-jwks (npm)): get-jwks contains fetch utils for JWKS keys. In versions prior to 11.0.2, a vulnerability in get-jwks can lead to cache…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-09-27
date_modified: 2025-09-29
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-59936"
kev: false
cvss: 9.4
epss: 0.00404
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-59936: get-jwks: poisoned JWKS cache allows post-fetch issuer validation bypass

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.4% , percentile 33: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 33% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes get-jwks (npm) <= 11.0.1, fixed in 11.0.2 . Check your lockfile, including transitive dependencies.

## What it is

get-jwks contains fetch utils for JWKS keys. In versions prior to 11.0.2, a vulnerability in get-jwks can lead to cache poisoning in the JWKS key-fetching mechanism. When the iss (issuer) claim is validated only after keys are retrieved from the cache, it is possible for cached keys from an unexpected issuer to be reused, resulting in a bypass of issuer validation. This design flaw enables a potential attack where a malicious actor crafts a pair of JWTs, the first one ensuring that a chosen public key is fetched and stored in the shared JWKS cache, and the second one leveraging that cached key to pass signature validation for a targeted iss value. The vulnerability will work only if the iss validation is done after the use of get-jwks for keys retrieval. This issue has been patched in version 11.0.2.

## Affected packages

- npm `get-jwks` <= 11.0.1 → fixed: 11.0.2

## Affected products (CVE record)

- nearform get-jwks: < 11.0.2

## Severity

- GitHub_M CVSS 3.0: 9.4 `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L`
- GitHub CVSS 3.1: 9.4 `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.40% probability of exploitation activity in the next 30 days; percentile 33.

## Sources

- [GitHub Advisory GHSA-qc2q-qhf3-235m](https://github.com/advisories/GHSA-qc2q-qhf3-235m)
- [CVE.org record CVE-2025-59936](https://www.cve.org/CVERecord?id=CVE-2025-59936)
- [NVD entry CVE-2025-59936](https://nvd.nist.gov/vuln/detail/CVE-2025-59936)
- [github.com](https://github.com/nearform/get-jwks/security/advisories/GHSA-qc2q-qhf3-235m)
- [github.com](https://github.com/nearform/get-jwks/commit/1706a177a80a1759fe68e3339dc5a219ce03ddb9)

---
Source page: https://erroneo.us/security/cve/CVE-2025-59936/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt