#VU86909 Out-of-bounds write in zlog - CVE-2021-43521

Vulnerability identifier: #VU86909

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-43521

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
zlog
Universal components / Libraries / Libraries used by multiple products

Vendor: Hardy Simpson

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing untrusted input within the zlog_conf_build_with_file() function in src/zlog/src/conf.c. A remote attacker can pass specially crafted input to the application, trigger an out-of-bounds write and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

zlog: 0.9.1 - 1.2.15

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External links
https://github.com/HardySimpson/zlog/issues/206

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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.