#VU109906 NULL pointer dereference in varnish-modules - CVE-2021-28543

Vulnerability identifier: #VU109906

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-2021-28543

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
varnish-modules
Server applications / Other server solutions

Vendor: Varnish Software

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 when processing headers. A remote attacker can pass specially crafted data to the application and perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

varnish-modules: before 0.17.0

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External links
https://varnish-cache.org/security/VSV00006.html

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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.