Leantime JSON-RPC Endpoint addUser improper authorization

published 2026-07-12 3 mo ago modified 2026-07-15 3 mo ago also EUVD-2026-43250

cvss: 6.3; 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 28%
public exploits: 0; none known

A vulnerability has been found in Leantime up to 3.8.0. This impacts the function editUser/addUser of the component JSON-RPC Endpoint. The manipulation of the argument role leads to improper authorization. The attack is possible to be carried out remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 3 mo ago (2026-07-15)

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

vuldb.com https://vuldb.com/submit/846167 referenced PoC, tagged "exploit" by a source, unverified
bytium.com https://bytium.com/insights/leantime-priv-escalation-vulnerability-low-priv-to-owner referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
CNA	3.1	6.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R
CNA	3.0	6.3	CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R
CNA	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P/E:POC/RL:ND/RC:UR
CNA	4.0	2.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA	3.1	6.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CNA	2.0	6.5	AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

n/a Leantime

Classification

Weakness

CWE-285 Improper Authorization
CWE-266 Incorrect Privilege Assignment

References

vuldb.com /submit/846167
third-party-advisory, exploit
bytium.com /insights/leantime-priv-escalation-vulnerability-low-priv-to-owner
exploit
vuldb.com /vuln/377838
vdb-entry, technical-description
vuldb.com /vuln/377838/cti
signature, permissions-required
vuldb.com /cve/CVE-2026-15509
third-party-advisory

Sources

CVE List CVE-2026-15509
NVD CVE-2026-15509

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.

Summary