CVE-2020-28935
5.5 · MEDIUMOverview
CVE-2020-28935 is a medium-severity vulnerability affecting nlnetlabs name_server_daemon. It was published on December 7, 2020 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbou
Remediation
Check the references section for vendor advisories and patches from nlnetlabs. Update name_server_daemon to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| nlnetlabs | name_server_daemon | >= 0, < 4.3.4 | Affected |
| nlnetlabs | unbound | >= 0, < 1.13.0 | Affected |
References
Frequently Asked Questions
What is CVE-2020-28935?
CVE-2020-28935 is a medium-severity vulnerability affecting nlnetlabs name_server_daemon. It was published on December 7, 2020 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2020-28935?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2020-28935?
Check the references section for vendor advisories and patches from nlnetlabs. Update name_server_daemon to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2020-28935?
CyberStrike's AI-powered security agents can automatically detect CVE-2020-28935 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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