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CVE-2026-48526

PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed

Published: May 28, 2026Updated: May 28, 2026 Sources: CVE List
NVD MITRE
7.4CVSS
HIGH

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, when the verifier is decoding JSON Web Tokens, while supporting both asymmetric and HMAC algorithms, the library does not validate use of JSON Web Keys in HMAC algorithm, allowing attacker to use the issuer public key as the secret key for HMAC algorithm. This vulnerability is fixed in 2.13.0.

EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None

Weaknesses

CWE-287CWE-287: Improper AuthenticationCWE-347CWE-347: Improper Verification of Cryptographic Signature

Affected Products

pyjwt
jpadilla

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

3 techniques
Collection
Initial Access
View detailed technique mapping

References

https://github.com/jpadilla/pyjwt/security/advisories/GHSA-xgmm-8j9v-c9wx
github.com

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