CVE-2021-33833 Memory corruption in n/a

What is CVE-2021-33833?

CVE-2021-33833 is a critical memory corruption vulnerability in Debian Debian Linux, published on 9 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

ConnMan (aka Connection Manager) 1.30 through 1.39 has a stack-based buffer overflow in uncompress in dnsproxy.c via NAME, RDATA, or RDLENGTH (for A or AAAA).

Weakness: CWE-787

Which versions are affected by CVE-2021-33833?

It affects 2 products.

Products include Debian Debian Linux, Intel Connection Manager.

How do I fix CVE-2021-33833?

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-2021-33833 being exploited?

There is no known exploitation of CVE-2021-33833 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-33833, GHSA-h4g6-6xx4-6g88, MGASA-2021-0331, UBUNTU-CVE-2021-33833.