CVE-2021-43991

lowpriority · track · 22EPSS 0.006 · 46 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.56% (46th) EPSS

CVSS 3.5 · low

Is it mine?

2 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-21

The Kentico Xperience CMS version 13.0 – 13.0.43 is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability (also known as Stored or Second-Order XSS). Persistent XSS vulnerabilities occur when the application stores and retrieves client supplied data without proper handling of dangerous content. This type of XSS vulnerability is exploited by submitting malicious script content to the application which is then retrieved and executed by other application users. The attacker could exploit this to conduct a range of attacks against users of the affected application such as session hijacking, account take over and accessing sensitive data.

cvss

Technical severity, 0–10. One row per scoring source.

6.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.5–6.8

v2.03.5lowAV:N/AC:M/Au:S/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 6.8 · impact 2.9

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.3 · impact 2.7

v3.16.8mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:Nsecondary · ENISA EU

v3.16.8mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:Nsecondary · info@appcheck-ng.comexploitability 2.3 · impact 4

v3.15mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USprimary

affected products (2)

Products and version ranges known to be affected.

Kentico Kentico Xperience XMS13.0 → 13.0.43enisa_euvdEU
kentico xperience13.0.0 → 13.0.43nvdUScpe:2.3:a:kentico:xperience:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-12-03modified 2026-06-17

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+51771 more

references (4)

External citations — patches, advisories, analysis.

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