CVE-2020-28042

ServiceStack before 5.9.2 mishandles JWT signature verification unless an application has a custom ValidateToken function that establishes a valid minimum length for a signature.

CVSS v3.1

5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v2.0

5.0 MEDIUMAV:N/AC:L/Au:N/C:N/I:P/A:N

EPSS

2.33% chance of exploitation in the next 30 days, 82th percentile

Published

2020-11-01

Updated

2024-08-04

Proof-of-concept exploits (2)

• https://www.shielder.it/advisories/servicestack-jwt-signature-verification-bypass/
• achmadismail173/jwt_exploit5★ · 2025-07-28

References

• CVE Record
• NVD entry

Related

• CVE-2015-9235
• CVE-2016-5431
• CVE-2018-0114
• CVE-2023-48238
• CVE-2020-28041
• CVE-2020-28047