High

CVE-2026-40321 — DotNetNuke.Core has stored cross-site-scripting (XSS) via SVG upload

DNN (formerly DotNetNuke) is an open-source web content management platform (CMS) in the Microsoft ecosystem. Prior to version 10.2.2, a user could upload a specially crafted SVG file that could include scripts that can target both authenticated and unauthenticated DNN users. The impact is increased if the scripts are run by a power user. Version 10.2.2 patches the issue.

Published Apr 17, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+4
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.36%

ahead of 28% of scored CVEs · Oct 14, 2026

Affects

Dnnsoftware

Dnn.Platform and 1 more

CVSS base

8.0

High · 2 source(s)

Prioritization reference: 8.1 provisional

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Dnnsoftware Dnn.Platform, Dnnsoftware Dotnetnuke).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Dnnsoftware	Dnn.Platform	version < 10.2.2	Vulnerable	CVE Program (cve.org) e CISA ADP
Dnnsoftware	Dotnetnuke	< 10.2.2	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

High

Privileges required

Low

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.1	CVSS 3.1	High	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP
8.0	CVSS 3.1	High	1.3	6.0	security-advisories@github.com via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-87

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.36%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · dnnsoftware/dnn.platform
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 8.0
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Apr 17, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

github.com/dnnsoftware/Dnn.Platform/security/advisories/GHSA-ffq7-898w-9jc4
Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
github.com/dnnsoftware/Dnn.Platform/releases/tag/v10.2.2
Release Notes, x_refsource_MISC, NIST National Vulnerability Database

Elsewhere on this site

Dnnsoftware
every CVE for this vendor

CWE-87
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-40306 DNN has same HostGUID for all new installs Apr 17, 2026
Medium CVE-2026-40305 DNN has Force Friend Request Acceptance Apr 17, 2026
Medium CVE-2020-37103 DotNetNuke 9.5 - Persistent Cross-Site Scripting Feb 3, 2026
Medium CVE-2026-24838 DotNetNuke.Core Vulnerable to Stored XSS via Module Title Jan 27, 2026
Medium CVE-2026-24837 DotNetNuke.Core Vulnerable to Stored XSS in Module Deletion Confirmation Modal Jan 27, 2026
Medium CVE-2026-24833 DotNetNuke.Core Vulnerable to Stored XSS in Module Description Jan 27, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-40321 is "DotNetNuke.Core has stored cross-site-scripting (XSS) via SVG upload", rated High. It affects Dnn.Platform (Dnnsoftware); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.0 describes technical severity. EPSS 0.36% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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