Improper Verification of Cryptographic Signature Affecting lemur package, versions [,1.9.2)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-LEMUR-17661119
- published28 Jun 2026
- disclosed25 Jun 2026
- creditim-rootkid
Introduced: 25 Jun 2026
CVE-2026-55165 (opens in a new tab)How to fix?
Upgrade lemur to version 1.9.2 or higher.
Overview
lemur is a Certificate management and orchestration service
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature in the decode_with_multiple_secrets process. An attacker can influence the cryptographic algorithm used for token verification by supplying a crafted JWT with a chosen alg header value. This allows the attacker to bypass intended algorithm restrictions and potentially forge tokens if a separate configuration disclosure exposes the signing secret. This is only exploitable if the attacker is able to obtain the signing secret through an independent disclosure or if the deployment migrates to asymmetric signing without correcting the algorithm selection logic.