CVE-2021-28831 Memory corruption in n/a

High 7.5 Published 19 Mar 2021 Updated 17 Dec 2025

An attacker can cause a denial of service via malformed gzip data due to improper error handling in BusyBox decompression.

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

What is CVE-2021-28831?

CVE-2021-28831 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 19 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

decompress_gunzip.c in BusyBox through 1.32.1 mishandles the error bit on the huft_build result pointer, with a resultant invalid free or segmentation fault, via malformed gzip data.

Weakness: CWE-755

Which versions are affected by CVE-2021-28831?

It affects 3 products.

Products include Busybox Busybox, Debian Debian Linux, Fedoraproject Fedora.

How do I fix CVE-2021-28831?

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-2021-28831 being exploited?

There is no known exploitation of CVE-2021-28831 in the wild and no public exploit code.

All Debian Debian Linux vulnerabilities

Sources

Also known as ALPINE-CVE-2021-28831, AZL-6342, CLSA-2021-1635459154, DEBIAN-CVE-2021-28831, DLA-2614-1, GHSA-7w53-225r-6vxv and 4 more.