Remote assertion failure via 16-bit length truncation in `dns_ncache_add()`
Summary
| CVE | CVE-2026-19667 |
|---|---|
| State | PUBLISHED |
| Assigner | isc |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-16 14:17:05 UTC |
| Updated | 2026-09-17 19:16:41 UTC |
| Description | If an attacker-controlled authoritative server can produce a negative answer that is exactly 65536 bytes, then a flaw in `named` results in a negative cache entry of 0 bytes. When this entry is subsequently read, `named` aborts. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.004860000 probability, percentile 0.409520000 (date 2026-09-20)
Problem Types: CWE-197 | CWE-197 CWE-197 Numeric Truncation Error
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | DECLARED | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | ISC | BIND 9 | affected 9.11.0 9.18.50 custom | Not specified |
| CNA | ISC | BIND 9 | affected 9.20.0 9.20.27 custom | Not specified |
| CNA | ISC | BIND 9 | affected 9.21.0 9.21.25 custom | Not specified |
| CNA | ISC | BIND 9 | affected 9.11.3-S1 9.18.50-S1 custom | Not specified |
| CNA | ISC | BIND 9 | affected 9.20.9-S1 9.20.27-S1 custom | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| downloads.isc.org/isc/bind9/9.20.29 | [email protected] | downloads.isc.org | |
| downloads.isc.org/isc/bind9/9.21.26 | [email protected] | downloads.isc.org | |
| kb.isc.org/docs/cve-2026-19667 | [email protected] | kb.isc.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: ISC would like to thank Rintaro Kawasugi for bringing this vulnerability to our attention. (en)
Additional Advisory Data
Solutions
CNA: Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.29, 9.21.26, or 9.20.29-S1.
Workarounds
CNA: No workarounds known.
Exploits
CNA: We are not aware of any active exploits.
There are currently no legacy QID mappings associated with this CVE.