#VU50779 Reachable Assertion in OpenLDAP - CVE-2021-27212

Vulnerability identifier: #VU50779

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-27212

CWE-ID: CWE-617

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenLDAP
Server applications / Directory software, identity management

Vendor: OpenLDAP.org

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a reachable assertion when processing LDAP packets within the issuerAndThisUpdateCheck() function in  schema_init.c. A remote attacker can send a specially crafted packet with a short timestamp to the slapd and perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

OpenLDAP: 2.4 - 2.4.57

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External links
https://bugs.openldap.org/show_bug.cgi?id=9454
https://git.openldap.org/openldap/openldap/-/commit/3539fc33212b528c56b716584f2c2994af7c30b0
https://git.openldap.org/openldap/openldap/-/commit/9badb73425a67768c09bcaed1a9c26c684af6c30

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.