Description
An issue has been found in PowerDNS Recursor 4.1.0 up to and including 4.3.0. It allows an attacker (with enough privileges to change the system's hostname) to cause disclosure of uninitialized memory content via a stack-based out-of-bounds read. It only occurs on systems where gethostname() does not have '\0' termination of the returned string if the hostname is larger than the supplied buffer. (Linux systems are not affected because the buffer is always large enough. OpenBSD systems are not affected because the returned hostname always has '\0' termination.) Under some conditions, this issue can lead to the writing of one '\0' byte out-of-bounds on the stack, causing a denial of service or possibly arbitrary code execution.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pdns-recursor | 4.3.1-1 | — |
| Debian 13 | pdns-recursor | 4.3.1-1 | — |
| Debian 12 | pdns-recursor | 4.3.1-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 18.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 16.04 LTS | pdns-recursor | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP1 | pdns-recursor | 4.1.12-bp151.4.3.1 | openSUSE-SU-2020:0698-1 |
| SUSE Package Hub 12 SP1 | pdns-recursor | 4.1.12-bp151.4.3.1 | openSUSE-SU-2020:0698-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | pdns-recursor | 4.5.5-1.3 | openSUSE-SU-2024:11157-1 |
| openSUSE Leap 15.1 | pdns-recursor | 4.1.12-bp151.4.3.1 | openSUSE-SU-2020:0698-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.10 | pdns-recursor | 4.1.16-r0 | — |
| Alpine v3.9 | pdns-recursor | 4.1.16-r0 | — |
Advisories 2
- openSUSE-SU-2024:11157-1 pdns-recursor-4.5.5-1.3 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0698-1 Security update for pdns-recursor SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2020-03.html
- openSUSE-SU-2020:0698 vendor-advisory
- FEDORA-2020-d9abb0c06d vendor-advisory
- FEDORA-2020-c0ff3df740 vendor-advisory