CVSS 4.0
8.7 highCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE-2026-123596
High (8.7) in hickory-dns hickory-dns. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
On this page
Hickory DNS hickory-proto through 0.26.0-alpha.1 and hickory-net 0.26.0-beta.1 before 0.26.2 contain a DNSSEC validation flaw in the validating recursor's NSEC handler that accepts parent-side ancestor-delegation NSEC records as proof of nonexistence for names below the zone cut. An on-path attacker, rogue parent nameserver, or attacker winning a port and TXID race can deliver one forged NXDOMAIN response built from genuinely signed parent NSEC records, causing authenticated denial of existing child-zone names cached for the negative TTL.
Severity
CVSS 3.1
8.8 highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 8th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-345 Insufficient Verification of Data Authenticity
- OWASP Top 10
- A08:2025 Software or Data Integrity Failures
- Published
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Explain CVE-2026-123596 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123596?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123596?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123596 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| hickory-dns | through 0.26.0-alpha.1 |
| hickory-dns | from 0.26.0-beta.1 before 0.26.2 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 13, 14 | rust-hickory-proto | no fix listed | DEBIAN-CVE-2026-123596 |
| Debian | 14 | rust-hickory-net | 0.26.3-1 | DEBIAN-CVE-2026-123596 |
| Ubuntu | 24.04:LTS, 26.04:LTS | rust-hickory-proto | no fix listed | UBUNTU-CVE-2026-123596 |
| Ubuntu | 26.10 | rust-hickory-net, rust-hickory-proto | no fix listed | UBUNTU-CVE-2026-123596 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-345 (12).