Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M

CVE-2026-55164Lemur: Plaintext password storage in Lemur user-update path

Medium 4.9

In plain English

A medium-severity security flaw in lemur from Netflix. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.9Medium

Exploit odds (30 days)0.3%top 78.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Lemur manages TLS certificate creation. Prior to 1.9.2, lemur.users.service.update assigned a replacement password directly to users.password, while lemur/users/models.py registered User.hash_password only for the before_insert event. Because no before_update listener ran, administrator-initiated password changes through PUT /api/1/users/ were committed as plaintext. The affected user could no longer authenticate normally because bcrypt verification received an unhashed value. A database, backup, replica, query-log, or administrative read compromise exposed immediately usable credentials without offline cracking. The fix registers hashing for before_update and avoids rehashing values that already have a bcrypt prefix. This issue is fixed in version 1.9.2.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	lemur	1.9.2	GHSA-q437-g7fv-2jvv
PyPI	lemur	1.9.2	PYSEC-2026-2587

Affected products (as reported)

Vendor	Product	Versions
Netflix	lemur	< 1.9.2

Weakness: CWE-256 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

References

https://github.com/Netflix/lemur/security/advisories/GHSA-q437-g7fv-2jvv x_refsource_CONFIRM
https://github.com/Netflix/lemur/commit/221c6d7275ac667bb8898ab48d2b96926a89c1c4 x_refsource_MISC
https://github.com/Netflix/lemur/releases/tag/v1.9.2 x_refsource_MISC