CVE-2026-3039

Description

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.

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

EPSS — Exploit Prediction

0.0008

Probability of exploitation

0.23%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-771 CWE-771

Affected Products

Vendor	Product	Versions
isc	bind	9.0.0 — 9.16.50
isc	bind	9.18.0 — 9.18.49
isc	bind	9.20.0 — 9.20.23
isc	bind	9.21.0 — 9.21.22

References

Advisories & Patches

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

Frequently Asked Questions

What is CVE-2026-3039? +

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

How severe is CVE-2026-3039? +

CVE-2026-3039 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. The EPSS score is 0.0008, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-3039? +

CVE-2026-3039 affects products from isc, specifically: bind. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-3039? +

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.

Related Vulnerabilities

CVE-2025-21090 6.5

Missing reference to active allocated resource for some Intel(R) Xeon(R) processors may allow an authenticated user to potentially enable denial …

CVE-2024-56343 4.3

IBM Verify Identity Access Digital Credentials 24.06 could allow an authenticated user to crash the service with a specially crafted …

CVE-2024-28872 8.9

The TLS certificate validation code is flawed. An attacker can obtain a TLS certificate from the Stork server and use …

CVE-2026-5947 7.5

Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS …

CVE-2026-5946 7.5

Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) …

CVE-2023-4408 7.5

The DNS message parsing code in `named` includes a section whose computational complexity is overly high. It does not cause …