Quick answers
- Is CVE-2026-50046 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-50046 being exploited in the wild.
- How severe is CVE-2026-50046?
- Medium severity, with a CVSS score of 5.9, published 22 July 2026.
- Which products and versions are affected?
- NLnet Labs Unbound 1.15.0 up to and including 1.25.1.
- Is there a fix for CVE-2026-50046?
- A patch was published on 2026-07-22: Fixed in Unbound 1.25.2 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-50046 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-50046?
- Check whether you run NLnet Labs Unbound at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A use-after-free (CWE-416) vulnerability exists in Unbound's DNS-over-TLS (DoT) forwarding logic. The TLS server name string is owned by the 'serviced_query' struct but is also referenced by the 'waiting_tcp' struct. If a query is 'jostled' (evicted) from the internal mesh during a DoT TCP handshake, the memory for the server name is freed; a subsequent TLS error causes a read-only dereference of this freed pointer, crashing the daemon. Exploitation requires the Unbound instance to have a stub or forward zone configured for DoT with an '#authname' suffix. An attacker must time queries to coincide with high server pressure and transient connection failures to trigger the vulnerable path. The issue is fixed in version 1.25.2.
Affected products
- NLnet Labs Unbound 1.15.0 up to and including 1.25.1
Timeline
- 2026-07-22: disclosed
- 2026-07-22: advisory
- 2026-07-22: patched: Fixed in Unbound 1.25.2