Vault Auth Header Forwarding CVE-2026-4525 (v2.0.0,1.21.5,1.20.10,1.19.16)
CVE-2026-4525 Published on April 17, 2026
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.
Vulnerability Analysis
CVE-2026-4525 can be exploited with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
Insertion of Sensitive Information Into Sent Data
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. Sensitive information could include data that is sensitive in and of itself (such as credentials or private messages), or otherwise useful in the further exploitation of the system (such as internal file system structure).
Products Associated with CVE-2026-4525
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Affected Versions
HashiCorp Vault:- Version 0.11.2 and below 2.0.0 is affected.
- Version 0.11.2 and below 2.0.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.