Chamilo LMS has Weak REST API Key Generation (Predictable)

published 2026-04-10 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-21565

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits: 0; none known

Chamilo LMS is a learning management system. Prior to 1.11.38 and 2.0.0-RC.3, REST API keys are generated using md5(time() + (user_id * 5) - rand(10000, 10000)). The rand(10000, 10000) call always returns exactly 10000 (min == max), making the formula effectively md5(timestamp + user_id*5 - 10000). An attacker who knows a username and approximate key creation time can brute-force the API key. This vulnerability is fixed in 1.11.38 and 2.0.0-RC.3.

Patch / fix

fixed in 2 links 2

chamilo chamilo 1.11.38, 2.0.0-rc.3
chamilo chamilo_lms 1.11.38, 2.0.0-rc.3

github.com/chamilo/chamilo-lms@4448701 commit
github.com/chamilo/chamilo-lms@e7400dd commit

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 6 mo ago (2026-04-13)

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

chamilo chamilo-lms

Classification

Weakness

CWE-330 Use of Insufficiently Random Values

References

Sources

CVE List CVE-2026-33710
NVD CVE-2026-33710

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary