CVE-2020-28042
CVE-2020-28042 is a medium-severity vulnerability in Servicestack with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- CVSS v2: 5.0
- EPSS exploit prediction: 2% (81st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-347
- Affected product: Servicestack
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2020-28042?
- CVE-2020-28042 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2020-28042 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-28042?
- CVE-2020-28042 affects Servicestack. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2020-28042?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2020-28042 published?
- CVE-2020-28042 was published on 2020-11-02 and last updated on 2026-06-17.
References
- https://forums.servicestack.net/t/servicestack-v5-9-2-released/8850
- https://github.com/ServiceStack/ServiceStack/commit/540d4060e877a03ae95343c1a8560a26768585ee
- https://www.shielder.it/advisories/servicestack-jwt-signature-verification-bypass/
- https://www.shielder.it/blog/2020/11/re-discovering-a-jwt-authentication-bypass-in-servicestack/
Affected products (1)
- cpe:2.3:a:servicestack:servicestack:*:*:*:*:*:*:*:*
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