CVE-2021-45955 Memory corruption in n/a

Critical 9.8 Published 31 Dec 2021 Updated 4 Aug 2024

Heap-based buffer overflow in Dnsmasq allows attackers to execute arbitrary code or cause denial of service via crafted packets.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2021-45955?

CVE-2021-45955 is a critical memory corruption vulnerability in n/a, published on 31 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.c) because of the lack of a proper bounds check upon pseudo header re-insertion. NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge." However, a contributor states that a security patch (mentioned in 016162.html) is needed

Weakness: CWE-787

Which versions are affected by CVE-2021-45955?

It affects 1 product.

Products include Thekelleys Dnsmasq.

How do I fix CVE-2021-45955?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2021-45955 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-45955 exists.

Sources

Also known as AZL-8962, GHSA-p5g5-mjp3-mr9m.