How severe is CVE-2026-3039?

CVE-2026-3039 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-3039 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-3039?

CVE-2026-3039 affects Isc Bind. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-3039?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-3039 have an EU (EUVD) identifier?

Yes. CVE-2026-3039 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31103.

When was CVE-2026-3039 published?

CVE-2026-3039 was published on 2026-05-20 and last updated on 2026-06-30.

CVE-2026-3039

CVE-2026-3039 is a high-severity vulnerability in Isc Bind with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-771.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31103
Weakness: CWE-771
Affected product: Isc Bind
Published: 2026-05-20
Last modified: 2026-06-30

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.

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.
How severe is CVE-2026-3039?: CVE-2026-3039 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-3039 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-3039?: CVE-2026-3039 affects Isc Bind. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-3039?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-3039 have an EU (EUVD) identifier?: Yes. CVE-2026-3039 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31103.
When was CVE-2026-3039 published?: CVE-2026-3039 was published on 2026-05-20 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*

More vulnerabilities in Isc Bind

CVE-2008-0122 — Critical (CVSS 10.0): Off-by-one error in the inet_network function in libbind in ISC BIND 9.4.2 and earlier, as used in libc in FreeBSD 6.2…
CVE-2001-0011 — Critical (CVSS 10.0): Buffer overflow in nslookupComplain function in BIND 4 allows remote attackers to gain root privileges.
CVE-2001-0013 — Critical (CVSS 10.0): Format string vulnerability in nslookupComplain function in BIND 4 allows remote attackers to gain root privileges.
CVE-2001-0010 — Critical (CVSS 10.0): Buffer overflow in transaction signature (TSIG) handling code in BIND 8 allows remote attackers to gain root privileges.
CVE-2000-1029 — Critical (CVSS 10.0): Buffer overflow in host command allows a remote attacker to execute arbitrary commands via a long response to an AXFR…
CVE-1999-0837 — Critical (CVSS 10.0): Denial of service in BIND by improperly closing TCP sessions via so_linger.

All CVEs affecting Isc Bind →

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