#VU61293 Off-by-one in Glibc - CVE-2021-3999

Vulnerability identifier: #VU61293

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-2021-3999

CWE-ID: CWE-193

Exploitation vector: Network

Exploit availability: No

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

Vendor: GNU

Description

The vulnerability allows a remote attacker to execute arbitrary code on the system.

The vulnerability exists due to an off-by-one error glibc getcwd() function. A remote attacker can pass specially crafted input to the application that is using the affected library version, trigger an off-by-one error and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Glibc: 2.0 - 2.34.9000

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External links
https://sourceware.org/bugzilla/show_bug.cgi?id=28769

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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.