Detections
Analytics

SCA: security update for lemur (GHSA-r9gp-7f88-9r54)

medium Tenable Cloud Security Plugin ID 443953

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - Lemur manages TLS certificate creation. Prior to 1.9.2, the JWT verifier in lemur/auth/service.py:130-137
 used fetch_token_header to read header_data["alg"] from an unverified token and passed that attacker-
 controlled value to decode_with_multiple_secrets. PyJWT 2.x rejects alg=none with the configured key, so
 the flaw is a defense-in-depth gap rather than a direct authentication bypass in the shipped
 configuration. The unpinned algorithm can become exploitable after an asymmetric-signing migration through
 algorithm confusion, and it weakens algorithm-based anomaly detection because the token chooses the
 recorded value. A separate disclosure of LEMUR_TOKEN_SECRET would also permit forged HS256 tokens,
 although that disclosure is an independent prerequisite. The fix introduces the server-controlled
 LEMUR_TOKEN_ALGORITHMS allowlist and defaults it to HS256. This issue is fixed in version 1.9.2.
 (CVE-2026-55165)

Solution

Update the lemur library and its related packages to version 1.9.2 or later.

See Also

https://github.com/advisories/GHSA-r9gp-7f88-9r54

Plugin Details

Severity: Medium

ID: 443953

Version: Revision 1.4

Type: Local

Family: SCA Checks

Published: 6/26/2026

Updated: 8/19/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 2.1

Percentile: 7.77

Vendor

Vendor Severity: Medium

CVSS v2

Risk Factor: Medium

Base Score: 4

Temporal Score: 3

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:P/A:N

CVSS Score Source: CVE-2026-55165

CVSS v3

Risk Factor: Medium

Base Score: 4.8

Temporal Score: 4.2

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 6/25/2026

Vulnerability Publication Date: 6/25/2026

Reference Information

CVE: CVE-2026-55165

cwe: CWE-347