CVE-2020-12403 Memory corruption in nss

Critical 9.1 Published 27 May 2021 Updated 4 Aug 2024

Out-of-bounds reads in NSS CHACHA20-POLY1305 implementation allow attackers to compromise confidentiality and system availability.

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

What is CVE-2020-12403?

CVE-2020-12403 is a critical memory corruption vulnerability in nss, published on 27 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A flaw was found in the way CHACHA20-POLY1305 was implemented in NSS in versions before 3.55. When using multi-part Chacha20, it could cause out-of-bounds reads. This issue was fixed by explicitly disabling multi-part ChaCha20 (which was not functioning correctly) and strictly enforcing tag length. The highest threat from this vulnerability is to confidentiality and system availability.

Weakness: CWE-125

Which versions are affected by CVE-2020-12403?

It affects 1 product.

Products include Mozilla Nss.

How do I fix CVE-2020-12403?

Upgrade to a fixed version.

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

Is CVE-2020-12403 being exploited?

There is no known exploitation of CVE-2020-12403 in the wild and no public exploit code.

Sources

Also known as ALPINE-CVE-2020-12403, AZL-6746, DEBIAN-CVE-2020-12403, GHSA-9h25-47mw-52hh, UBUNTU-CVE-2020-12403, USN-4476-1.