ORY Fosite is a security first OAuth2 & OpenID Connect framework for Go. In Fosite before version 0.34.1, the OAuth 2.0 Client's registered redirect URLs and the redirect URL provided at the OAuth2 Authorization Endpoint where compared using strings.ToLower while they should have been compared with a simple string match. This allows an attacker to register a client with allowed redirect URL https://example.com/callback. Then perform an OAuth2 flow and requesting redirect URL https://example.com/CALLBACK. Instead of an error (invalid redirect URL), the browser is redirected to https://example.com/CALLBACK with a potentially successful OAuth2 response, depending on the state of the overall OAuth2 flow (the user might still deny the request for example). This vulnerability has been patched in ORY Fosite v0.34.1.
CVE-2020-15234
This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.8%, top 46% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.1
- EG Score
- 6.1(medium)
- EG Risk
- 32(Track)EG Risk 32/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity61% × 45%Exploitation1% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 53.8%
- KEV
- Not listed
Published
October 2, 2020
Last Modified
November 21, 2024
References (4)
- security-advisories@githubhttps://github.com/ory/fosite/commit/cdee51ebe721bfc8acca0fd0b86b030ca70867bf
- security-advisories@githubhttps://github.com/ory/fosite/security/advisories/GHSA-grfp-q2mm-hfp6
- af854a3a-2127-422b-91ae-364da2661108https://github.com/ory/fosite/commit/cdee51ebe721bfc8acca0fd0b86b030ca70867bf
- af854a3a-2127-422b-91ae-364da2661108https://github.com/ory/fosite/security/advisories/GHSA-grfp-q2mm-hfp6
Affected Packages
(1 across 1 ecosystem)
Go(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| github.com/ory/fosite | — | 0.34.1 | — |
Weakness Classification(3)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 47× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
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Frequently asked(5)
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