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Fencer Intel
medium 6.1

CVE-2020-26877 json

ApiFest OAuth 2.0 Server 0.3.1 does not validate the redirect URI in accordance with RFC 6749 and is susceptible to an open redirector atta…

published 4y ago modified 4mo ago also EUVD-2020-19412

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

ApiFest OAuth 2.0 Server 0.3.1 does not validate the redirect URI in accordance with RFC 6749 and is susceptible to an open redirector attack. Specifically, it directly sends an authorization code to the redirect URI submitted with the authorization request, without checking whether the redirect URI is registered by the client who initiated the request. This allows an attacker to craft a request with a manipulated redirect URI (redirect_uri parameter), which is under the attacker's control, and consequently obtain the leaked authorization code when the server redirects the client to the manipulated redirect URI with an authorization code. NOTE: this is similar to CVE-2019-3778.

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Exploit prediction

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.