`CVE-2021-20323` Keycloak

Affected software	Keycloak
Severity	6.1 Medium CVSS 3.1 2 scores
Fixed in	`17.0.0`
Weakness	Cross-site scripting (CWE-79)
Published	25 Mar 2022
Updated	17 Jun 2026

Description

A POST based reflected Cross Site Scripting vulnerability on has been identified in Keycloak.

Exploitation status

Working exploit published

A reviewed exploit catalogue lists ready-to-run exploit code for this CVE.

CISA KEV not listed
VulnCheck KEV not listed
CISA Vulnrichment no assessment published
Indexed PoC 4 indexed Published artifacts you can open, in GitHub PoC, Nuclei; first seen 2022-12-07.
EPSS 37% chance in 30 days A model's forecast, not a report of exploitation. Higher than 99% of all scored CVEs.

2 of these are GitHub repositories with fewer than 5 stars. They are listed for reference and don't count toward the exploitation status above.

Index	Artifact	Stars	First seen
GitHub PoC	ndmalc/CVE-2021-20323	12	2022-12-07
GitHub PoC	A POST based reflected Cross Site Scripting vulnerability on has been identified in Keycloak.	3	2024-01-11
GitHub PoC	Exploitation Scanner Cross Site Scripting vulnerability in Keycloak.	2	2024-07-07
Nuclei	Keycloak 10.0.0 - 18.0.0 - Cross-Site Scripting

Waratek protection

Mitigation candidate

A kind of vulnerability Waratek's rules address, with exploit code published or exploitation reported. No rule exists and none is planned yet. The decision below says what we found to build a rule from.

Protection none
Action unverified
Review automated Inferred
Record active

Decided by	A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug
Finding	A Red Hat Bugzilla ticket (https://bugzilla.redhat.com/show_bug.cgi?id=2013577) tracks the fix. That makes this CVE a candidate for an ARMR patch rule. No rule exists and none is scheduled: whether one can be derived depends on reading the upstream change the ticket links.
Candidate fix	https://bugzilla.redhat.com/show_bug.cgi?id=2013577 : a Red Hat bug: the triage, which links onward to the fix

Decided by

A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

Finding

A Red Hat Bugzilla ticket (https://bugzilla.redhat.com/show_bug.cgi?id=2013577) tracks the fix. That makes this CVE a candidate for an ARMR patch rule. No rule exists and none is scheduled: whether one can be derived depends on reading the upstream change the ticket links.

Candidate fix

https://bugzilla.redhat.com/show_bug.cgi?id=2013577 : a Red Hat bug: the triage, which links onward to the fix

CVSS

6.1 MEDIUM v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

Version Score Band Vector Assigner Type

CVSS 3.1 6.1 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N NVD Primary published

CVSS 2.0 4.3 none AV:N/AC:M/Au:N/C:N/I:P/A:N NVD Primary

Version	Score	Band	Vector	Assigner	Type
CVSS 3.1	6.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`	NVD	Primary	published
CVSS 2.0	4.3	none	`AV:N/AC:M/Au:N/C:N/I:P/A:N`	NVD	Primary

Affected software and releases

Maven packages

Affected and fixed versions, from OSV.dev

Package Introduced Fixed Last affected

org.keycloak:keycloak-core 15.0.0 17.0.0 unbounded

Package	Introduced	Fixed	Last affected
`org.keycloak:keycloak-core`	15.0.0	`17.0.0`	unbounded

Products and versions

2 products, 2 version entries

Source	Vendor	Product	Scheme	Affected versions
osv	org.keycloak	keycloak-core	generic	≥ 15.0.0 and ＜ 17.0.0
nvd	redhat	keycloak	generic	＜ 17.0.0

Source

Vendor

Product

Scheme

Affected versions

osv

org.keycloak

keycloak-core

generic

≥ 15.0.0 and ＜ 17.0.0

nvd

redhat

keycloak

generic

＜ 17.0.0

References

URL	Tags
https://bugzilla.redhat.com/show_bug.cgi?id=2013577	bugzilla
https://github.com/keycloak/keycloak	PACKAGE

URL

Timeline

Published	2022-03-25	By the CVE Program.
NVD record modified	2026-06-17	NVD's own last-modified date for this record.

Published

2022-03-25

By the CVE Program.

NVD record modified

2026-06-17

NVD's own last-modified date for this record.

How VRT decided (17 of 24 rules ran)

17 of 24 rules ran. The rest didn't run because an earlier rule had already settled the CVE.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? the first rule that matches decides

1 rejected no match CVE Program withdrawal of this identifier

scope: Is it a vulnerability Waratek protects? the first rule that matches decides

2 armr-patch-file no match An ARMR patch file on disk for this CVE

3 armr-secure-rule-file no match An ARMR security-rule template on disk for this CVE

4 manual-classification no match A researcher's recorded decision for this specific CVE

5 manual classification no match Manual classification of this CVE in the legacy dataset

6 non-java-upstream no match A root cause in non-Java code: an OS kernel, a C library, or a bundled runtime

7 oracle-component no match The defect being in a component of a tracked product the agent does not reach: JavaFX, the Java SE installer, the JInitiator browser plug-in, the native WebLogic proxy plug-in, or a native part of Oracle Application Server or Collaboration Suite (HTTP Server, Web Cache, Internet Directory, mail and calendar servers). Oracle gives these no CPE of their own and names them only in the description.

8 java-client-side no match Oracle's own risk-matrix note saying the CVE is reached only through untrusted code in the Java sandbox (applets, Web Start) or only through a client installation of Java, so a server running its own trusted code is not exposed

9 osv-maven matched In scope Maven packages: org.keycloak:keycloak-core

10 cna-maven-package not reached An affected Maven artifact named by the CNA itself

11 known-cpe-product not reached An NVD CPE naming a product ARMR tracks

12 cna-cpe-product not reached A CPE the CNA published naming a tracked product. Oracle publishes these on advisory day, months before NVD.

13 oracle-advisory-family not reached A tracked product family named in Oracle's own risk matrix. CPE cannot carry a suite name, only a module.

14 cna-named-product not reached A tracked product named in words by the CVE's own CNA, on a record with no CPE yet. Apache and Eclipse publish these on advisory day, before NVD adds CPE data.

15 non-deployable-product not reached The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached

16 unmatched-product not reached No tracked product matched above, and none present at all

disposition: What do we do about one that is? every rule runs

17 patch-hint decided it matched Mitigation candidate References include candidate fix URL (bugzilla tier): https://bugzilla.redhat.com/show_bug.cgi?id=2013577

18 open-source-maven skipped The affected package being open source on Maven, so the fix can be read

19 poc-derivable skipped An indexed exploit clearing the evidence bar to reverse-engineer, where there is no source to read

20 no-exploit skipped Nothing to build a rule from yet: no published exploit, no CISA record of exploitation and no source-level change to read

21 secure-rule-match no match A vulnerability class already blocked by an ARMR security rule

22 exploited-no-fix-or-poc skipped Somebody exploiting this CVE (a CISA or VulnCheck KEV listing, or a CISA verdict of active exploitation), with no fix, source code or PoC to build a rule from

23 below-action-threshold withheld Has 4 known POC(s) clearing the evidence bar — requires review despite MEDIUM severity

24 no-exploit-published no match A CISA or VulnCheck KEV listing, a CISA verdict of active exploitation, a reviewed exploit catalogue, or a GitHub PoC with 5 or more stars carries this CVE — exploit code is in use or published, so it stays a candidate

Products the scope rules checked

The products this CVE's record names, and whether VRT tracks each one. The scope rules decided on these.

Vendor Product Tracked CPE Source

redhat keycloak tracked cpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:* yaml

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