OAuth client impersonation via expired JWT replay
Published Jul 30, 2026 · Updated Jul 30, 2026
Authentication bypass in malach.it Boruta 2.3.0 through 2.3.6 allows attackers to impersonate OAuth clients using expired JWT assertions. The check_expiration/1 helper confirms only that exp exists, while token_config/0 supplies no validator to compare it with the current time. Exploitation requires a previously valid signed assertion and a client configured for client_secret_jwt or private_key_jwt, and grants access tokens with that client's privileges.
Summary
What happened
Authentication bypass in malach.it Boruta 2.3.0 through 2.3.6 allows attackers to impersonate OAuth clients using expired JWT assertions. The check_expiration/1 helper confirms only that exp exists, while token_config/0 supplies no validator to compare it with the current time. Exploitation requires a previously valid signed assertion and a client configured for client_secret_jwt or private_key_jwt, and grants access tokens with that client's privileges.
The record
- CVE
- CVE-2026-53431
- Published
- Jul 30, 2026
- Updated
- Jul 30, 2026
- Vendor
- malach.it
- Product
- Boruta
- Classifications
- CWE-287, CWE-294, CAPEC-60, T1550.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 30, 2026CVE publishedPublication date reported by the CVE source.
- Jul 30, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.3.0 <2.3.7
- Affected versionversion=5bfbe1c5443bffe71cf1bf954bbdff61327d9a83 <* changes=[{"at":"5204f88f9b2cdd9637a755337ed5f99185be5474","status":"unaffected"},{"at":"69363432aa36760fc5438e4e17115d0f7c1b925a","status":"unaffected"}]
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Expired JWT client assertion replay procedureproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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