keycloak-core: open redirect via "form_post.jwt" JARM response mode

Description

An incomplete fix was found in Keycloak Core patch. An attacker can steal authorization codes or tokens from clients using a wildcard in the JARM response mode "form_post.jwt". It is observed that changing the response_mode parameter in the original proof of concept from "form_post" to "form_post.jwt" can bypass the security patch implemented to address CVE-2023-6134.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2024-01-23 14:43:50 UTC
Updated
2024-12-26 15:09:07 UTC
GitHub reviewed
2024-01-23 14:43:50 UTC

EPSS Score

Score Percentile
0.84% 74.50%

CVSS Scores

Base score Version Severity Vector
4.6 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-601 URL Redirection to Untrusted Site ('Open Redirect')

Credits

  • PontusHanssen (finder)
  • kasperkarlsson (finder)
  • Chetven (analyst)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
maven org.keycloak:keycloak-core < 23.0.4 23.0.4

References

cvelogic Threat Intelligence