CVE-2020-27840 Memory corruption in samba

What is CVE-2020-27840?

CVE-2020-27840 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 12 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 samba. Spaces used in a string around a domain name (DN), while supposed to be ignored, can cause invalid DN strings with spaces to instead write a zero-byte into out-of-bounds memory, resulting in a crash. The highest threat from this vulnerability is to system availability.

Weakness: CWE-125

Which versions are affected by CVE-2020-27840?

It affects 3 products.

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

How do I fix CVE-2020-27840?

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-2020-27840 being exploited?

There is no known exploitation of CVE-2020-27840 in the wild and no public exploit code.

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• 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 ALPINE-CVE-2020-27840, AZL-36997, AZL-45414, AZL-7351, DEBIAN-CVE-2020-27840, ECHO-3b38-c4b7-f66d and 2 more.