CVE-2020-28042
MEDIUM
5.3
CVSS Score
Published: November 1, 2020 at 04:50 AM UTC
Updated: June 17, 2026 at 03:10 AM UTC
1 product affected across 1 vendorServiceStack
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Severity
MEDIUM5.3
Exploit prediction
EPSS 2%
Description
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.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
v < 5.9.2
Affected range stops below 5.9.2, so it looks safe — our inference, not a vendor statement
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
References (4)
x_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://forums.servicestack.net/t/servicestack-v5-9-2-released/8850x_refsource_MISCPatchThird Party Advisory
Source: [email protected]
https://github.com/ServiceStack/ServiceStack/commit/540d4060e877a03ae95343c1a8560a26768585eex_refsource_MISCExploitThird Party Advisory
Source: [email protected]
https://www.shielder.it/advisories/servicestack-jwt-signature-verification-bypass/x_refsource_MISCExploitThird Party Advisory
Source: [email protected]
https://www.shielder.it/blog/2020/11/re-discovering-a-jwt-authentication-bypass-in-servicestack/CVSS
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- NONE
- Integrity
- LOW
- Availability
- NONE
Vector?
Quick Info
StatusMODIFIED
CWE
CWE-347
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