CVE-2026-3039

HIGH 7.5

BIND 9 server memory exhaustion during GSS-API TKEY negotiation

CVSS Score

7.5

EPSS Score

0.0%

EPSS Percentile

0th

BIND servers that are configured to use TKEY-based authentication via GSS-API tokens are vulnerable to excessive memory consumption when receiving and processing maliciously-constructed packets. Typically these servers will be found in Active Directory integrated DNS deployments and/or Kerberos-secured DNS environments. This issue affects BIND 9 versions 9.0.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.9.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.

CWE	CWE-771
Vendor	isc
Product	bind 9
Published	May 20, 2026
Last Updated	May 20, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

ISC / BIND 9

9.0.0 ≤ 9.16.50 9.18.0 ≤ 9.18.48 9.20.0 ≤ 9.20.22 9.21.0 ≤ 9.21.21 9.9.3-S1 ≤ 9.16.50-S1 9.18.11-S1 ≤ 9.18.48-S1 9.20.9-S1 ≤ 9.20.22-S1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

kb.isc.org: https://kb.isc.org/docs/cve-2026-3039 downloads.isc.org: https://downloads.isc.org/isc/bind9/9.18.49 downloads.isc.org: https://downloads.isc.org/isc/bind9/9.20.23 downloads.isc.org: https://downloads.isc.org/isc/bind9/9.21.22

Credits

ISC would like to thank Vitaly Simonovich for bringing this vulnerability to our attention.