Quick answers
- Is CVE-2026-123571 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-123571 being exploited in the wild.
- How severe is CVE-2026-123571?
- High severity, with a CVSS score of 7.5, published 8 November 2026.
- Which products and versions are affected?
- Hickory-Dns Hickory DNS 0.26.0 before 0.26.2.
- Is there a fix for CVE-2026-123571?
- Yes: fixed in 0.26.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-123571 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-123571?
- Check whether you run Hickory-Dns Hickory DNS 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.
How to fix
- Fixed in: 0.26.2
Technical details
An integer underflow vulnerability exists in TSIG RDATA decoding when processing malformed DNS wire format records. A remote attacker can trigger unchecked subtraction that causes a panic in applications compiled with overflow checks enabled (common in dev/debug builds). No authentication or user interaction is required; the attacker simply sends a crafted TSIG record over the network.
Affected products
- hickory-dns hickory-dns 0.26.0 before 0.26.2
Timeline
- 2026-09-03: disclosed
- 2026-11-08: advisory