CVE-2026-1519 HIGH

CVE-2026-1519: Excessive NSEC3 iterations cause high CPU load during insecure delegation validation

Vendor Isc

Product BIND 9

Weakness CWE-606

Published March 25, 2026

Last update June 30, 2026

View on NVD All CVEs

CVSS base score

7.5/10

Attack vector Network

Attack complexity Low

Privileges required None

User interaction None

Confidentiality None

Integrity None

CVSS vector

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

What the vulnerability does

01Description

If a BIND resolver is performing DNSSEC validation and encounters a maliciously crafted zone, the resolver may consume excessive CPU. Authoritative-only servers are generally unaffected, although there are circumstances where authoritative servers may make recursive queries (see: https://kb.isc.org/docs/why-does-my-authoritative-server-make-recursive-queries). This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.46, 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.46-S1, and 9.20.9-S1 through 9.20.20-S1.

Key dates

02Disclosure timeline

March 25, 2026 CVE published

June 30, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-1519 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/606.html

Identifiers

CVE CVE-2026-1519

CWE CWE-606

CVSS 7.5 / HIGH

Affected versions

Vendor Isc

Product BIND 9

Affected ≥ 9.11.0 and ≤ 9.16.50

Vendor Isc

Product BIND 9

Affected ≥ 9.18.0 and ≤ 9.18.46

Vendor Isc

Product BIND 9

Affected ≥ 9.20.0 and ≤ 9.20.20

Vendor Isc

Product BIND 9

Affected ≥ 9.21.0 and ≤ 9.21.19

Vendor Isc

Product BIND 9

Affected ≥ 9.11.3-S1 and ≤ 9.16.50-S1

Vendor Isc

Product BIND 9

Affected ≥ 9.18.11-S1 and ≤ 9.18.46-S1

Vendor Isc

Product BIND 9

Affected ≥ 9.20.9-S1 and ≤ 9.20.20-S1