PatchTheCVECVE-2026-44621: With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with
CVE-2026-44621 is a medium-severity flaw (CVSS 5.9) affecting unbound. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and the iterator queries an author
Why this priority
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 5.9 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.2% (top 85%) |
| CISA exploited list | No |
| Weakness | CWE-754 |
| Published | 2026-07-22 |
| Last modified | 2026-10-24 |
Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-44621?
unbound: upgrade to 1.25.2. Exact commands for each OS are on this page.
Is CVE-2026-44621 being exploited?
CVE-2026-44621 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-44621 affect?
CVE-2026-44621 affects unbound. Severity is medium (CVSS 5.9). With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and libunbound needs to call 'libw
How urgent is CVE-2026-44621?
Priority 29/100. Remotely exploitable, no login, no user action
Related CVEs
- CVE-2026-32665 HIGH 7.5 UPGRADE In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, when downstream DNS-over-QUIC (DoQ) is enabled, the f
- CVE-2026-40691 HIGH 7.5 UPGRADE In Unbound 1.9.0 up to and including 1.25.1, when a DNSCrypt query is received over TCP, the routine that encr
- CVE-2026-55973 HIGH 7.5 UPGRADE In NLnet Labs Unbound 1.23.0 up to and including 1.25.1, when 'dns-error-reporting: yes' is set, the EDNS Repo
- CVE-2026-50252 CRITICAL 9.3 UPGRADE In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to serve a
- CVE-2026-50045 MEDIUM 5.3 UPGRADE In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, a single client query for a deeply nested name under