Unsigned payload acceptance via empty JWS signature list
Published Sep 28, 2026 · Updated Sep 28, 2026
Signature verification bypass in Authlib 1.7.2 allows remote attackers to submit an unsigned JSON JWS payload for acceptance. JsonWebSignature.deserialize_json() initializes verification as successful and skips its signature-checking loop when the general JWS signatures list is empty. Exploitation requires an application to pass attacker-controlled JSON JWS input to this API and trust the returned payload for an authentication or authorization decision.
Summary
What happened
Signature verification bypass in Authlib 1.7.2 allows remote attackers to submit an unsigned JSON JWS payload for acceptance. JsonWebSignature.deserialize_json() initializes verification as successful and skips its signature-checking loop when the general JWS signatures list is empty. Exploitation requires an application to pass attacker-controlled JSON JWS input to this API and trust the returned payload for an authentication or authorization decision.
The record
- CVE
- CVE-2026-96760
- Published
- Sep 28, 2026
- Updated
- Sep 28, 2026
- Vendor
- Authlib
- Product
- Authlib
- Classifications
- T1606
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 28, 2026CVE publishedPublication date reported by the CVE source.
- Sep 28, 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?
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- Affected versionversion=1.7.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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