CVE-2021-3121 Improper Input Validation in GoGo Protobuf

High 8.6 Published 11 Jan 2021 Updated 3 Aug 2024

Attackers can exploit missing index validation in GoGo Protobuf to cause memory corruption, potentially leading to code execution or denial of service.

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

What is CVE-2021-3121?

CVE-2021-3121 is a high-severity memory corruption vulnerability in n/a, published on 11 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An issue was discovered in GoGo Protobuf before 1.3.2. plugin/unmarshal/unmarshal.go lacks certain index validation, aka the "skippy peanut butter" issue.

Weakness: CWE-129

Which versions are affected by CVE-2021-3121?

5 open source packages ship an affected version, including github.com/gogo/protobuf, consul and protobuf. It affects 2 products.

Package	Affected	Fixed in
`github.com/gogo/protobuf` Go	All versions	`1.3.2`
`github.com/gogo/protobuf` Go	All versions	`1.3.2`
`github.com/gogo/protobuf` Go	All versions	`1.3.2`
`consul` Bitnami	All versions	`1.8.15, 1.9.9, 1.10.2`
`protobuf` Bitnami	All versions	`1.3.2`

Linux distribution packages (15)

`kubernetes1.18` SUSE:Enterprise Storage 7.1	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise Server 15 SP3-LTSS	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise Server 15 SP4-LTSS	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise Server for SAP Applications 15 SP3	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` SUSE:Linux Enterprise Server for SAP Applications 15 SP4	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` openSUSE:Leap 15.6	All versions	`1.18.20-150200.5.25.1`
`kubernetes1.18` openSUSE:Tumbleweed	All versions	`1.18.20-1.2`
`kubernetes1.19` openSUSE:Tumbleweed	All versions	`1.19.15-1.1`
`kubernetes1.20` openSUSE:Tumbleweed	All versions	`1.20.11-1.1`
`kubernetes1.21` openSUSE:Tumbleweed	All versions	`1.21.5-1.1`
`velero` openSUSE:Tumbleweed	All versions	`1.7.0-1.1`
`velero-plugin-for-aws` openSUSE:Tumbleweed	All versions	`1.3.0-1.1`

Products include Golang Protobuf, Hashicorp Consul.

How do I fix CVE-2021-3121?

Upgrade github.com/gogo/protobuf to 1.3.2 or later.

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

Is CVE-2021-3121 being exploited?

There is no known exploitation of CVE-2021-3121 in the wild and no public exploit code.

Sources

Also known as ALPINE-CVE-2021-3121, BIT-consul-2021-3121, BIT-protobuf-2021-3121, CLEANSTART-2025-UP04115, CLEANSTART-2026-DT87304, DEBIAN-CVE-2021-3121 and 10 more.