How severe is CVE-2020-15233?

CVE-2020-15233 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-15233 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-15233?

CVE-2020-15233 affects Ory Fosite. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-15233?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-15233 published?

CVE-2020-15233 was published on 2020-10-02 and last updated on 2026-06-17.

CVE-2020-15233

CVE-2020-15233 is a medium-severity vulnerability in Ory Fosite with a CVSS 3.x base score of 6.1. 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-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.9
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Ory Fosite
Published: 2020-10-02
Last modified: 2026-06-17

Description

ORY Fosite is a security first OAuth2 & OpenID Connect framework for Go. In Fosite from version 0.30.2 and before version 0.34.1, there is an issue in which an an attacker can override the registered redirect URL by performing an OAuth flow and requesting a redirect URL that is to the loopback adapter. Attackers can provide both custom URL query parameters to their loopback redirect URL, as well as actually overriding the host of the registered redirect URL. These attacks are only applicable in scenarios where the attacker has access over the loopback interface. This vulnerability has been patched in ORY Fosite v0.34.1.

Frequently asked questions

What is CVE-2020-15233?: ORY Fosite is a security first OAuth2 & OpenID Connect framework for Go. In Fosite from version 0.30.2 and before version 0.34.1, there is an issue in which an an attacker can override the registered redirect URL by performing an OAuth flow and requesting a redirect URL that is to the loopback adapter. Attackers can provide both custom URL query parameters to their loopback redirect URL, as well as actually overriding the host of the registered redirect URL. These attacks are only applicable in scenarios where the attacker has access over the loopback interface. This vulnerability has been patched in ORY Fosite v0.34.1.
How severe is CVE-2020-15233?: CVE-2020-15233 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-15233 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-15233?: CVE-2020-15233 affects Ory Fosite. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-15233?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-15233 published?: CVE-2020-15233 was published on 2020-10-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ory:fosite:*:*:*:*:*:*:*:*

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CVE-2020-15222 — High (CVSS 8.1): In ORY Fosite (the security first OAuth2 & OpenID Connect framework for Go) before version 0.31.0, when using…
CVE-2020-15223 — High (CVSS 8.0): In ORY Fosite (the security first OAuth2 & OpenID Connect framework for Go) before version 0.34.0, the…
CVE-2020-15234 — Medium (CVSS 6.1): ORY Fosite is a security first OAuth2 & OpenID Connect framework for Go. In Fosite before version 0.34.1, the OAuth 2.0…

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