Widely deployed DNS server Unbound; critical infrastructure component.
CVE-2026-42944
Remote heap overflow in Unbound DNS via EDNS options.
Is CVE-2026-42944 being exploited?
Not confirmed. CVE-2026-42944 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.84% probability of exploitation in the next 30 days.
How severe is CVE-2026-42944?
CVE-2026-42944 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-42944?
Yes. A fix has been recorded for CVE-2026-42944. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-42944 affect?
CVE-2026-42944 affects NLnet Labs Unbound 1.14.0 - 1.25.0. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-42944?
Upgrade to 1.25.1+; apply EDNS dedupe/truncation fixes.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote heap overflow in Unbound when processing multiple EDNS options; can crash DNS service.
Patch when possible
- affected>= 1.14.0 and < 1.25.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.