`CVE-2021-20323`

6.1 Medium Mitigation candidate

Description

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

CWE-79 · Cross-site scripting

Exploitation Status

Working exploit published

A reviewed exploit catalogue carries this CVE. Somebody has published code a stranger can run.

CVSS E:P

CISA 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 prediction, not an observation. Higher than 98% of all scored CVEs.

2 of these are GitHub repositories below the 5★ evidence bar. They are listed because a person may still want to open one; they do not count toward the exploit maturity above.

Index	Artifact	Stars	First seen
GitHub PoC	ndmalc/CVE-2021-20323	13	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.	1	2024-07-07
Nuclei	Keycloak 10.0.0 - 18.0.0 - Cross-Site Scripting

Waratek Defense Posture

Mitigation candidate

A defect of the type ARMR addresses, with a fix path to work from and a working exploit already published. This is a claim on attention, not a scheduling commitment: no rule exists and none is scheduled.

Protection none
Action unverified patch rule
Review automated inferred
Record active

Decided by patch-hint : A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug

Finding Red Hat published an advisory () confirming a fix exists, and the linked Bugzilla ticket (https://bugzilla.redhat.com/show_bug.cgi?id=2013577) points to the upstream OpenJDK source patch. 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 actual change.

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	`patch-hint` : A reference pointing at the upstream fix: a commit, a PR, a Red Hat bug
Finding	Red Hat published an advisory () confirming a fix exists, and the linked Bugzilla ticket (https://bugzilla.redhat.com/show_bug.cgi?id=2013577) points to the upstream OpenJDK source patch. 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 actual change.
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

VRT selects the newest version's highest entry and publishes it as cvssScore, newest rather than largest because scores are not comparable across versions, and highest rather than first because the first entry is frequently a CNA placeholder scoring 0.0 over NVD's own analysis.

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 no band published 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	no band published	`AV:N/AC:M/Au:N/C:N/I:P/A:N`	NVD	Primary

Affected Software & Releases

☕ Maven Library Packages

Artifact coordinates and fix boundaries from OSV.dev

Package Coordinate Introduced Fixed Last affected

org.keycloak:keycloak-core 15.0.0 17.0.0 unbounded

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

🖥️ Product CPEs & Version Ranges

2 product(s) over 2 version claims (uncapped)

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 Last modified 2026-06-17

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.

Pipeline policy audit (15 of 21 rules evaluated)

15 of 21 rules ran. The rest were never reached, because an earlier stage settled the CVE, a distinct claim from a rule that ran and found nothing.

# Rule Outcome Status Detail

identity: Does this identifier describe a vulnerability at all? first match wins

1 rejected no-match CVE Program withdrawal of this identifier

scope: Is the vulnerability ARMR's to address? first match wins

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 native WebLogic proxy plug-in. Oracle gives these no CPE of their own and names them only in the description.

8 osv-maven matched Queued for review Maven packages: org.keycloak:keycloak-core

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

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

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

12 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.

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

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

disposition: What do we do about one that is? cumulative: every rule gets a turn

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

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

17 poc-derivable skipped An indexed exploit to reverse-engineer, where there is no source to read

18 no-exploit skipped With no fix path, a public exploit, or a CISA record of one

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

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

21 no-exploit-published no-match A KEV listing, a CISA verdict of active exploitation, or a reviewed exploit catalogue carries this CVE — somebody has published a working exploit, so it stays a candidate

What the scope rules read

The products the record named, and whether known-products.yaml tracks them. This is the evidence the scope stage decided on.

Vendor Product Tracked CPE Source

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

Raw stored JSON document for this CVE ↗ · NVD ↗ · CVE.org ↗