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Fencer Vulns
critical 9.1

CVE-2021-26715 json

Server Side Request Forgery (SSRF) in org.mitre:openid-connect-server

published 2021-03-25 5 y ago modified 2026-06-17 4 mo ago also GHSA-792r-mh2q-p8qp , EUVD-2021-0993

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

The OpenID Connect server implementation for MITREid Connect through 1.3.3 contains a Server Side Request Forgery (SSRF) vulnerability. The vulnerability arises due to unsafe usage of the logo_uri parameter in the Dynamic Client Registration request. An unauthenticated attacker can make a HTTP request from the vulnerable server to any address in the internal network and obtain its response (which might, for example, have a JavaScript payload for resultant XSS). The issue can be exploited to bypass network boundaries, obtain sensitive data, or attack other hosts in the internal network.

Exploit prediction

1.49% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • portswigger.net https://portswigger.net/research/hidden-oauth-attack-vectors referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N
GitHub 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven org.mitre:openid-connect-server
<=1.3.3
 no fix listed

Classification

Weakness
  • CWE-918 Server-Side Request Forgery

References

Sources

Fencer Vulns 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.