CVE-2026-19667 (CVSS 7.5)

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-197 CWE-197

References

Other References

https://downloads.isc.org/isc/bind9/9.20.29 https://downloads.isc.org/isc/bind9/9.21.26 https://kb.isc.org/docs/cve-2026-19667

Frequently Asked Questions

What is CVE-2026-19667? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-19667? +

CVE-2026-19667 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2026-19667? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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