---
title: "CVE-2026-53939: OpenIDC cjose - Cryptographic Key Generation Flaw"
description: "OpenIDC cjose 0.6.1 through 0.6.2.5 contains a cryptographic key generation flaw caused by zeroed content-encryption key in AES-CBC-HMAC JWE encryption, letting attackers decrypt and forge JWE content, exploit requires use of affected algorithms."
url: https://panop.io/threat-heartbeat/CVE-2026-53939/
---

# CVE-2026-53939 OpenIDC cjose - Cryptographic Key Generation Flaw

OpenIDC cjose 0.6.1 through 0.6.2.5 contains a cryptographic key generation flaw caused by zeroed content-encryption key in AES-CBC-HMAC JWE encryption, letting attackers decrypt and forge JWE content, exploit requires use of affected algorithms.

CVSS base score 9.1 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.24% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-53939)

## Details

Type

Cryptographic Key Generation Flaw

Impact

Information Disclosure, Data Tampering

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Published

9 September 2026

Updated

15 October 2026

Weakness

[CWE-321](https://cwe.mitre.org/data/definitions/321.html)

## Vendor fix

Upgrade to version 0.6.2.6 or later; alternatively use AES-GCM encryption or supply a secure CEK.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-53939](https://nvd.nist.gov/vuln/detail/CVE-2026-53939)
- [https://github.com/OpenIDC/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9](https://github.com/OpenIDC/cjose/commit/2a6e5bd969fa20059fb00913fb9f57d77ea6a4d9)
- [https://github.com/OpenIDC/cjose/releases/tag/v0.6.2.6](https://github.com/OpenIDC/cjose/releases/tag/v0.6.2.6)
- [https://github.com/OpenIDC/cjose/security/advisories/GHSA-f6wf-pqg3-6wqq](https://github.com/OpenIDC/cjose/security/advisories/GHSA-f6wf-pqg3-6wqq)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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