Security readout for executives and security teams
Plain-English summary
Grafana OSS deployments using Auth Proxy with IPv6 allow-lists may trust a much broader IPv6 range than intended. If an entry lacks an explicit mask, it defaults to /32 instead of a single host. This can let unauthorized remote clients bypass the whitelist and gain access paths protected by Auth Proxy.
Executive priority
Treat this as high priority where Grafana Auth Proxy is internet-facing or protects sensitive operational data. The fix appears configuration-focused, but affected environments should be found quickly because the issue can undermine an access boundary.
Technical view
CVE-2026-33376 is a CWE-1188 Auth Proxy IPv6 allow-list misconfiguration flaw in Grafana OSS. IPv6 entries without an explicit CIDR mask default to /32. Explicitly masked entries are not affected. CVSS 3.1 is 7.4: network reachable, no privileges or user interaction, high confidentiality and integrity impact, high attack complexity.
Likely exposure
Exposure is limited to Grafana OSS instances using the Auth Proxy feature with IPv6 allow-list entries missing explicit masks. Okta, SAML, LDAP, and other authentication methods are stated as unaffected by this issue.
Exploitation context
The bundle does not report known active exploitation, and KEV is false. Exploitation appears configuration-dependent and high complexity, but the impact could be serious where Auth Proxy guards sensitive dashboards or administrative functions.
Researcher notes
The strongest evidence is the Grafana advisory and CVE data. The bundle names affected Grafana OSS versions but does not provide exploit evidence or complete patch status. Validation should focus on Auth Proxy configuration semantics, not offensive bypass testing.
Mitigation direction
- Add explicit CIDR masks to every IPv6 Auth Proxy allow-list entry.
- Use /128 for single IPv6 hosts unless vendor guidance says otherwise.
- Review Grafana’s advisory for fixed-version or upgrade guidance.
- Confirm non-Auth Proxy authentication paths do not rely on this allow-list.
- Prioritize externally reachable Grafana instances first.
Validation and detection
- Inventory Grafana OSS instances matching the versions listed in the bundle.
- Identify instances with Auth Proxy enabled.
- Review IPv6 allow-list entries for missing explicit masks.
- Confirm intended single-host entries use /128.
- Document that Okta, SAML, LDAP-only instances are out of scope.
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
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ATT&CK lookup starting points
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CWE-1188: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-33376 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
- 7.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
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
1 official scoreWe 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:H/PR:N/UI:N/S:U/C:H/I:H/A:N2.25.2GRAFANAVulnerability scoring details
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
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.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://grafana.com/security/security-advisories/cve-2026-33376CVE reference, GRAFANA · vendor-advisory
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.
Initialization of a Resource with an Insecure Default
Initialization of a Resource with an Insecure Default represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.