What’s Vulnerable › Vulnerabilities

CVE-2026-13204: Unexpected exit in certain situations with NSEC and NSEC3 both present

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-22 · updated 2026-10-24
• Weakness: CWE-617

Description

If a provably insecure domain is covered by both an NSEC and NSEC3 record at the parent, and there exist an RRSIG for only one of these types, then BIND may exit unexpectedly with an assertion while validating this proof. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.24-S1.

Affected products

• ISC BIND: from 9.11.0 through 9.18.50; from 9.20.0 through 9.20.24; from 9.21.0 through 9.21.23; from 9.11.3-S1 through 9.18.50-S1; from 9.20.9-S1 through 9.20.24-S1

References

• https://downloads.isc.org/isc/bind9/9.20.26
• https://downloads.isc.org/isc/bind9/9.21.24
• https://kb.isc.org/docs/cve-2026-13204

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