Denial of service in unzip

1) NULL pointer dereference

EUVDB-ID: #VU68298

Risk: Medium

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-4217

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

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

The vulnerability exists due to a NULL pointer dereference error in unzip when handling Unicode strings. A remote attacker can trick the victim to open a specially crafted archive and perform a denial of service (DoS) attack.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

UnZip: 5.2 - 6.10c22

CPE2.3

• cpe:2.3:a:info-zip:unzip:5.2:*:*:*:*:*:*:*
• cpe:2.3:a:info-zip:unzip:5.3:*:*:*:*:*:*:*
• cpe:2.3:a:info-zip:unzip:5.31:*:*:*:*:*:*:*

External links

https://bugs.launchpad.net/ubuntu/+source/unzip/+bug/1957077
https://bugzilla.redhat.com/show_bug.cgi?id=2044583
https://access.redhat.com/security/cve/CVE-2021-4217

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to open a a specially crafted archive.

Is there known malware, which exploits this vulnerability?

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