Vulnerability Details CVE-2026-114615
Authlib is a Python library which builds OAuth and OpenID Connect servers. From 1.3.1 until 1.9.0, OctKey.import_key() checks asymmetric-key markers only at byte zero while Authlib's PEM loaders accept leading whitespace, comments, or a byte-order mark. In deployments that use the documented mixed algorithm registry and already configure verification with PEM or certificate bytes containing such a prefix, an unauthenticated attacker who knows those same public-key bytes can use them as an HMAC secret and forge HS256 tokens with arbitrary identity or authorization claims. This is a bypass of the remediation for CVE-2024-37568. The module-level jwt object reaches OctKey.import_key() in authlib/jose/rfc7518/oct_key.py, where POSSIBLE_UNSAFE_KEYS fails to identify prefixed asymmetric key material. This issue is fixed in version 1.9.0.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 9.1%
CVSS Severity
CVSS v3 Score 7.4
Products affected by CVE-2026-114615
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cpe:2.3:a:authlib:authlib:1.3.1
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cpe:2.3:a:authlib:authlib:1.3.2
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cpe:2.3:a:authlib:authlib:1.4.0
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cpe:2.3:a:authlib:authlib:1.4.1
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cpe:2.3:a:authlib:authlib:1.5.0
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cpe:2.3:a:authlib:authlib:1.5.1
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cpe:2.3:a:authlib:authlib:1.5.2
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cpe:2.3:a:authlib:authlib:1.6.0
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cpe:2.3:a:authlib:authlib:1.6.1
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cpe:2.3:a:authlib:authlib:1.6.10
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cpe:2.3:a:authlib:authlib:1.6.11
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cpe:2.3:a:authlib:authlib:1.6.12
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cpe:2.3:a:authlib:authlib:1.6.2
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cpe:2.3:a:authlib:authlib:1.6.3
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cpe:2.3:a:authlib:authlib:1.6.4
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cpe:2.3:a:authlib:authlib:1.6.5
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cpe:2.3:a:authlib:authlib:1.6.6
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cpe:2.3:a:authlib:authlib:1.6.7
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cpe:2.3:a:authlib:authlib:1.6.8
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cpe:2.3:a:authlib:authlib:1.6.9
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cpe:2.3:a:authlib:authlib:1.7.0
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cpe:2.3:a:authlib:authlib:1.7.1
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cpe:2.3:a:authlib:authlib:1.7.2