Security readout for executives and security teams
Plain-English summary
Grafana Auth Proxy can treat an IPv6 allow-list entry without an explicit mask as a /32 network instead of one address. This may trust far more IPv6 sources than intended, allowing unauthorized access and changes through Auth Proxy. Other authentication methods, including Okta, SAML, and LDAP, are not affected by this issue.
Executive priority
Prioritize promptly where internet-accessible or sensitive Grafana deployments use Auth Proxy with IPv6 allow-lists. The issue can undermine an authentication trust boundary and expose dashboards or permit unauthorized changes. Lower the priority only after confirming Auth Proxy is unused or every IPv6 entry already has an explicit, correct mask.
Technical view
The flaw is an insecure default in Auth Proxy IPv6 allow-list parsing. Unmasked IPv6 entries default to /32, creating an overly broad trusted range. CVSS 3.1 rates it 7.4: remotely reachable, unauthenticated, high complexity, with high confidentiality and integrity impact but no availability impact.
Likely exposure
Exposure requires Grafana OSS using Auth Proxy with IPv6 allow-list entries that omit an explicit prefix length. Installations using explicit masks are not affected by this behavior. The bundle identifies specific releases from 9.4.0 through 13.0.1; confirm exact applicability against Grafana’s advisory.
Exploitation context
The CVE is not listed in KEV, and the supplied sources do not report active exploitation or a public exploit. Exploitation is network-based, requires no privileges or user interaction, but is rated high complexity. Risk depends on whether an attacker-controlled IPv6 address falls within an unintentionally trusted /32 range.
Researcher notes
CWE-1188 reflects an insecure default initialization. The decisive condition is omitted IPv6 prefix length, not IPv6 use alone. The record’s default status is unaffected outside the identified versions, but version interpretation should be confirmed with Grafana. No evidence supplied supports active exploitation, availability impact, or impact to non-Auth-Proxy authentication.
Mitigation direction
- Add an explicit intended prefix length to every Auth Proxy IPv6 allow-list entry, usually /128 for one address.
- Review Grafana’s security advisory for supported fixed versions or additional vendor remediation guidance.
- Restrict network access to Grafana while configuration review and remediation are underway.
- Do not alter unaffected Okta, SAML, or LDAP configurations solely for this CVE.
Validation and detection
- Confirm whether Auth Proxy and IPv6 source allow-listing are enabled.
- Inventory every IPv6 allow-list entry and identify addresses lacking an explicit prefix length.
- Verify single-host entries use /128 and network entries use the deliberately intended prefix.
- Confirm the deployed Grafana OSS version against the vendor advisory’s affected and fixed-version guidance.
- After remediation, verify only intended IPv6 sources are accepted through Auth Proxy.
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.