CVE-2021-40874

An issue was discovered in LemonLDAP::NG (aka lemonldap-ng) 2.0.13. When using the RESTServer...

9.8 CriticalFix available

An issue was discovered in LemonLDAP::NG (aka lemonldap-ng) 2.0.13. When using the RESTServer plug-in to operate a REST password validation service (for another LemonLDAP::NG instance, for example) and using the Kerberos authentication method combined with another method with the Combination authentication plug-in, any password will be recognized as valid for an existing user.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

1.19%Up 0.3 points since Jul 18, 2022

What each source reports

NVD Score used 9.8

Record: CVE-2021-40874
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-287
Updated: 2026-11-02

CVE List No score

Record: CVE-2021-40874
Updated: 2026-11-02

EUVDEUVD-2021-28029 No score

Record: EUVD-2021-28029
Updated: 2026-11-03

GitHub AdvisoriesGHSA-gvrq-49rv-2rq7 9.8

An issue was discovered in LemonLDAP::NG (aka lemonldap-ng) 2.0.13. When using the RESTServer...

Record: GHSA-gvrq-49rv-2rq7
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-287
Updated: 2026-11-02

OSV 9.8

Record: CVE-2021-40874
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-40874 9.8

Record: DEBIAN-CVE-2021-40874
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-40874 9.8

Record: UBUNTU-CVE-2021-40874
CVSS 3.1: 9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`lemonldap-ng` Debian:12	before 2.0.14+ds-1	2.0.14+ds-1
`lemonldap-ng` Debian:13	before 2.0.14+ds-1	2.0.14+ds-1
`lemonldap-ng` Debian:14	before 2.0.14+ds-1	2.0.14+ds-1
`lemonldap-ng` Ubuntu:16.04:LTS	All versions, plus listed versions 1.3.3-11.4.6-11.4.6-21.4.6-3	None known
`lemonldap-ng` Ubuntu:18.04:LTS	All versions, plus listed versions 1.9.10-11.9.13-21.9.14-11.9.15-11.9.16-2	None known
`lemonldap-ng` Ubuntu:20.04:LTS	All versions, plus listed versions 2.0.5+ds-22.0.6+ds-22.0.7+ds-2	None known
`lemonldap-ng` Ubuntu:22.04:LTS	All versions, plus listed versions 2.0.11+ds-42.0.13+ds-32.0.13+ds-3ubuntu1	None known
`lemonldap-ng` Ubuntu:24.04:LTS	All versions, plus listed versions 2.16.2+ds-12.17.1+ds-12.17.2+ds-12.17.2+ds-22.18.1+ds-12.18.2+ds-1	None known
`lemonldap-ng` Ubuntu:25.10	All versions, plus listed versions 2.20.2+ds-1build12.21.0+ds-3	None known
`lemonldap-ng` Ubuntu:26.10	All versions, plus listed versions 2.22.2+ds-12.22.3+ds-12.23.0+ds-32.23.0+ds-42.23.2+ds-12.23.2+ds-22.23.3+ds-1	None known
`lemonldap-ng` Ubuntu:26.04:LTS	All versions, plus listed versions 2.21.0+ds-32.22.0+ds-22.22.1+ds-12.22.2+ds-1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-40874 is a critical vulnerability (CVSS 9.8) in Debian Linux, published July 17, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.19%, the 68th percentile. Fixed in lemonldap-ng 2.0.14+ds-1.