CVE-2026-77860
NVD: In NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb... NVD: A malicious actor can exploit this by controlling an authoritative zone with short TTL, so cached entries expire quickly. NVD: Each 'slow' query, one the attacker's authoritative never answers, is followed by one query for an expired cached name, which is answered immediately via the 'serve-expired' path and decrements the counter twice.
3.7 Severity
LOW EPSS
0.0027 (20) KEV
-
Source-published summary
NVD: In NLnetLabs Unbound 1.20.0 up to and including 1.26.0, a vulnerability on the 'serve-expired' code path can cause a double decrement on the 'wait-limit' counter per client IP essentially bypassing one of the counter measures that was introduced for DNSBomb... NVD: A malicious actor can exploit this by controlling an authoritative zone with short TTL, so cached entries expire quickly. NVD: Each 'slow' query, one the attacker's authoritative never answers, is followed by one query for an expired cached name, which is answered immediately via the 'serve-expired' path and decrements the counter twice.
Possible impact
This low severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for defensive exposure review.
Affected context
Affected product or version requires source confirmation.
Remediation / advisory
Remediation reference present; patch status requires confirmation in the linked advisory.
Why it matters
This low severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for defensive exposure review.; CVSS 3.7 (LOW); EPSS percentile 20; not listed in KEV; Remediation reference present; patch status requires confirmation in the linked advisory; sources: NVD.
What to verify
Confirm affected product/version, vendor advisory, patch or mitigation, and exposure.
Exposure hint
exposure unknown
Impact tags
Urgency reasons
Source-derived note
Summary derived from NVD description; unsafe procedural detail is not shown.
Redaction metadata
- source summary used
- True
- fallback summary used
- False
- unsafe procedural detail present
- false
- raw source displayed
- false
- public summary redacted
- true
Remediation handoff
Public-safe static handoff for human/Codex remediation planning. Scan, patch, external execution, and auto remediation are disabled.
Safety note
This radar shows source-published defensive context only. Exploit procedures, exploit strings, scanner commands, and auto-remediation are not provided.