Authentication bypass via colliding JWKS cache keys
Published Sep 27, 2025 · Updated Sep 27, 2025
Cache poisoning in Nearform get-jwks before 11.0.2 allows remote attackers to forge JWTs accepted by consuming applications. getPublicKey joins attacker-controlled alg, kid, and issuer-domain values with unescaped colons, allowing distinct inputs to resolve to one cached key. The attack requires issuer validation after key retrieval and two crafted JWTs: one seeds the shared cache with an attacker key, and the next reuses it under the targeted issuer.
Summary
What happened
Cache poisoning in Nearform get-jwks before 11.0.2 allows remote attackers to forge JWTs accepted by consuming applications. getPublicKey joins attacker-controlled alg, kid, and issuer-domain values with unescaped colons, allowing distinct inputs to resolve to one cached key. The attack requires issuer validation after key retrieval and two crafted JWTs: one seeds the shared cache with an attacker key, and the next reuses it under the targeted issuer.
The record
- CVE
- CVE-2025-59936
- Published
- Sep 27, 2025
- Updated
- Sep 27, 2025
- Vendor
- Nearform
- Product
- get-jwks
- Classifications
- CWE-116, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 27, 2025CVE publishedPublication date reported by the CVE source.
- Sep 27, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 11.0.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream two-JWT cache-poisoning proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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