BIND 9: Missing Reference to Active Allocated Resource
CVE-2026-3039 is a high-severity missing reference to active allocated resource vulnerability in BIND 9 from ISC, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected BIND 9 versions: 9.0.0 through 9.16.50; 9.18.0 through 9.18.48; 9.20.0 through 9.20.22, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.09% chance of exploitation within 30 days, higher than 66% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Bind to 9.18.49 or 9.20.23 or 9.21.22, whichever matches your release line, or a later version.
- Read the advisory on kb.isc.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| ISC | BIND 9 | 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; 9.20.9-S1 through 9.20.22-S1 | Not stated |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.16 | Not specified in the record | Not stated |
| Red Hat | Red Hat Hardened Images | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4 | Not specified in the record | Not stated |
| ISC | Bind | 9.0.0 through 9.16.50; 9.18.0 up to, but not including, 9.18.49; 9.20.0 up to, but not including, 9.20.23; 9.21.0 up to, but not including, 9.21.22 | 9.18.49, 9.20.23, 9.21.22 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (isc.org).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (isc.org) |
| CVSS 3.1 | 7.5 | High | CNA |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Reference to Active Allocated Resource
The product does not properly maintain a reference to a resource that has been allocated, which prevents the resource from being reclaimed.
More Missing Reference to Active Allocated Resource vulnerabilities (CWE-771)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other references
- access.redhat.com/errata/RHSA-2026:20334
- access.redhat.com/errata/RHSA-2026:23360
- access.redhat.com/errata/RHSA-2026:24338
- access.redhat.com/errata/RHSA-2026:24339
- access.redhat.com/errata/RHSA-2026:24367
- access.redhat.com/errata/RHSA-2026:24368
- access.redhat.com/errata/RHSA-2026:55441
- access.redhat.com/errata/RHSA-2026:57189
- access.redhat.com/errata/RHSA-2026:60383
- access.redhat.com/errata/RHSA-2026:62549
- access.redhat.com/errata/RHSA-2026:65851
- access.redhat.com/security/cve/CVE-2026-3039
- bugzilla.redhat.com/show_bug.cgi?id=2479767
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3039.json
Other vulnerabilities in BIND 9
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Missing Reference to Active Allocated Resource vulnerabilities
- 7.4 High severity
- 8.6 High severity
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