Boruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges.
This issue affects boruta: from 2.3.0 before 2.3.7.
Analysis and contextual insights are available on OpenCVE Cloud.
Vendor Workaround
Restrict the use of JWT-based client authentication (client_secret_jwt and private_key_jwt) to highly trusted clients, and prefer non-JWT client authentication methods (client_secret_basic or client_secret_post) where possible. Where JWT client authentication must remain enabled, issue short-lived client assertions and protect them from exposure in application logs, fronting proxies, browser tooling, and observability systems to reduce the window for replay.
Tracking
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Thu, 30 Jul 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Malach-it boruta
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| Vendors & Products |
Malach-it boruta
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Thu, 30 Jul 2026 17:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Thu, 30 Jul 2026 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing OAuth client after the assertion has expired. Boruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges. This issue affects boruta: from 2.3.0 before 2.3.7. | |
| Title | Boruta accepts expired JWT client assertions due to missing exp claim validation | |
| First Time appeared |
Malach-it
Malach-it boruta Auth |
|
| Weaknesses | CWE-294 | |
| CPEs | cpe:2.3:a:malach-it:boruta_auth:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Malach-it
Malach-it boruta Auth |
|
| References |
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|
| Metrics |
cvssV4_0
|
Status: PUBLISHED
Assigner: EEF
Published:
Updated: 2026-07-30T16:13:22.708Z
Reserved: 2026-06-09T11:01:47.529Z
Link: CVE-2026-53431
Updated: 2026-07-30T16:13:13.574Z
No data.
No data.
OpenCVE Enrichment
Updated: 2026-07-30T19:15:04Z
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CWE-294
Authentication Bypass by Capture-replay