Possible ZONEMD verification bypass window
CVSS score
4.4
EPSS probability
%0.2
Risk score
0.0
Published
26 d ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-77955 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check: yes) which are located below (but not at) a trust anchor allow for an attack window where (tampered with) zone contents are served (or stored to disk) prior to the ZONEMD integrity check. This is caused by the needed DS/DNSKEY asynchronous resolution that needs to happen before the ZONEMD check completes. If a zonefile is written to disk (zonefile: option) while the ZONEMD check failed, the tampered data are reloaded on startup and available until ZONEMD verification concludes again. If verification fails, the data is not served any more but still persists on disk for future reloads.
IMPACT: Affected Products and Software
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 4.4 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N | NVD |
| 4.4 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:N | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-77955 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-77955 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
CVSS Vector Radar Chart
4.4 / 10Vulnerability Scoring Details
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:NYama doğrulandı
Weakness Type (CWE & CAPEC)
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Get this vulnerability through the API
Affected products, version ranges, exploitation status and patch information in a single request, with a free key.
curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-77955"