CVE-2026-4525 | Vault Token Leaked to Backends via Authorization: Bearer Passthrough Header

If a Vault auth mount is configured to pass through the "Authorization" header, and the "Authorization" header is used to authenticate to Vault, Vault forwarded the Vault token to the auth plugin backend. Fixed in 2.0.0, 1.21.5, 1.20.10, and 1.19.16.

Published: 2026-04-17 Last update: 2026-04-27 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-4525 is rated Low Risk (31/100): CVSS High severity, with low exploitation likelihood (EPSS 0.01%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-4525

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-17 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-4525

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 5.9 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]

Weakness enumeration for CVE-2026-4525

GitHub Security Advisory for CVE-2026-4525

GHSA-72gw-fmmr-c4r4 · Severity: high · Ecosystem: go — HashiCorp Vault May Expose Tokens to Auth Plugins Due to Incorrect Header Sanitization

OS Trackers for CVE-2026-4525

vendor priority summary link
redhat high — https://access.redhat.com/security/cve/CVE-2026-4525

Affected software / configurations for CVE-2026-4525

Vendor Product Version Raw CPE
hashicorp vault >= 0.11.2, < 1.19.16 cpe:2.3:a:hashicorp:vault:*:*:*:*:enterprise:*:*:*
hashicorp vault >= 0.11.2, < 2.0.0 cpe:2.3:a:hashicorp:vault:*:*:*:*:-:*:*:*
hashicorp vault >= 1.20.0, < 1.20.10 cpe:2.3:a:hashicorp:vault:*:*:*:*:enterprise:*:*:*
hashicorp vault >= 1.21.0, < 1.21.5 cpe:2.3:a:hashicorp:vault:*:*:*:*:enterprise:*:*:*

References for CVE-2026-4525

cvelogic Threat Intelligence