Security readout for executives and security teams
Plain-English summary
Vault could accidentally hand a user’s Vault token to an authentication plugin backend when a specific Authorization header passthrough configuration is used. That token may allow access matching the token’s privileges. The issue is high severity, but the public bundle does not cite active exploitation.
Executive priority
Treat this as a priority patch and configuration review for Vault environments, especially where custom or third-party auth plugins are used. Business risk depends on whether privileged Vault tokens reached backend systems outside their intended trust boundary.
Technical view
When an auth mount passes through the Authorization header and that same header authenticates to Vault, Vault forwarded the Vault bearer token to the auth plugin backend. This is CWE-201 information exposure with potential confidentiality, integrity, and availability impact. Fixed releases are 2.0.0, 1.21.5, 1.20.10, and 1.19.16.
Likely exposure
Exposure is limited to HashiCorp Vault or Vault Enterprise deployments using affected auth mount behavior: Authorization header passthrough plus Authorization-based Vault authentication. Environments without that configuration are less likely exposed based on the provided description.
Exploitation context
No active exploitation is cited in the source bundle, and KEV is false. The CVSS vector indicates network reachability, low privileges, no user interaction, and high complexity, so exploitation appears configuration-dependent rather than broadly automatic.
Researcher notes
The public data is specific about the vulnerable condition and fixed versions, but incomplete on exact affected version ranges. Avoid assuming all Vault deployments are exploitable; validate the auth mount passthrough behavior and Authorization-based authentication path.
Mitigation direction
- Upgrade Vault to 2.0.0, 1.21.5, 1.20.10, or 1.19.16.
- Review HashiCorp advisory guidance for supported upgrade paths.
- Audit auth mounts for Authorization header passthrough configuration.
- Assess whether any auth plugin backend received Vault tokens.
- Follow vendor guidance for token response if exposure is suspected.
Validation and detection
- Inventory Vault and Vault Enterprise versions across environments.
- Identify auth mounts configured to pass through Authorization headers.
- Confirm whether clients authenticate to Vault using Authorization bearer tokens.
- Check whether affected auth plugin backends could log or retain headers.
- Document systems not using the risky header passthrough pattern.
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-201: Information exposure and cloud metadata lookup
Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-4525 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:H/PR:L/UI:N/S:U/C:H/I:H/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:H/PR:L/UI:N/S:U/C:H/I:H/A:H1.65.9HashiCorpCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H1.65.9redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/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
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-04-17T04:01:24.934Z: Reported to Red Hat.
- 2026-04-17T03:00:47.561Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://discuss.hashicorp.com/t/hcsec-2026-07-vault-may-expose-tokens-to-auth-plugins-due-to-incorrect-header-sanitization/77344CVE reference, HashiCorp
- https://access.redhat.com/security/cve/CVE-2026-4525CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2459107CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4525.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
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.
Insertion of Sensitive Information Into Sent Data
Insertion of Sensitive Information Into Sent Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.