Security readout for executives and security teams
Plain-English summary
This vulnerability can let an unauthenticated network attacker make certain BIND 9 DNS servers consume excessive memory. The main business risk is DNS disruption, especially in Active Directory integrated or Kerberos-secured DNS environments using TKEY authentication with GSS-API tokens.
Executive priority
Treat as a high-priority DNS availability issue. Patch exposed or identity-integrated DNS servers quickly because disruption to DNS can affect authentication, application access, and internal operations, even though the provided evidence does not show active exploitation.
Technical view
CVE-2026-3039 affects BIND 9 servers configured for TKEY-based authentication using GSS-API tokens. Maliciously constructed packets can cause excessive memory consumption. The CVSS 3.1 score is 7.5, with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely where BIND 9 supports Kerberos-secured DNS, Active Directory integrated DNS, or TKEY/GSS-API authentication. Affected ranges include multiple ISC BIND 9 stable and subscription branches through 9.16.50, 9.18.48, 9.20.22, and 9.21.21.
Exploitation context
The provided bundle does not show CISA KEV listing or cited evidence of active exploitation. The attack is network reachable and unauthenticated when vulnerable configuration is present, but evidence here supports denial of service through memory exhaustion only.
Researcher notes
Key scoping variable is configuration: BIND 9 must use TKEY-based authentication via GSS-API tokens. The bundle names CWE-770 and CWE-771 resource allocation issues and provides fixed ISC release references, but does not include packet details or exploit indicators.
Mitigation direction
- Upgrade affected ISC BIND 9 deployments to a fixed vendor release.
- Use ISC 9.18.49, 9.20.23, or 9.21.22 where applicable.
- Apply relevant Red Hat errata for vendor-packaged BIND deployments.
- Prioritize AD integrated and Kerberos-secured DNS environments.
- Check ISC or OS vendor guidance before changing TKEY/GSS-API settings.
Validation and detection
- Inventory BIND 9 versions across authoritative and recursive DNS servers.
- Identify servers configured for TKEY authentication using GSS-API tokens.
- Confirm packages are newer than the affected branch limits.
- Verify vendor advisory applicability for Red Hat-managed systems.
- Monitor DNS service availability and abnormal memory growth after remediation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-770: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-771: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-3039 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6iscCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Made public.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-05-19T09:48:19.212Z: Reported to Red Hat.
- 2026-05-21T12:24:11.051Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- CVE-2026-3039CVE reference, isc · vendor-advisory
- https://downloads.isc.org/isc/bind9/9.18.49CVE reference, isc · patch
- https://downloads.isc.org/isc/bind9/9.20.23CVE reference, isc · patch
- https://downloads.isc.org/isc/bind9/9.21.22CVE reference, isc · patch
- https://access.redhat.com/security/cve/CVE-2026-3039CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2479767CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3039.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:24338CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:24339CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:23360CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:24367CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:24368CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:20334CVE reference, redhat-SADP · vendor-advisory, x_refsource_REDHAT
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Missing Reference to Active Allocated Resource
Missing Reference to Active Allocated Resource represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.