Skip to content
Noroxi
CVE-2025-22602· NVD / CVE Program· CNA GitHub_M

Stored DOM-based XSS (without CSP) via video placeholders in Discourse

Discourse is an open source platform for community discussion. In affected versions an attacker can execute arbitrary JavaScript on users' browsers by posting a malicious video placeholder html element. This issue only affects sites with CSP disabled. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should enable CSP.

MediumCVSS 6.1 · v3.1—No exploit No fix recorded

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help
Published
Feb 4, 2025
Updated
Jun 17, 2026
EPSS
0.4% · 28th percentile
Follow this CVE

Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.1
CNA · GitHub_M
6.5
0.4 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
discoursediscourse

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • discourse discoursebefore 3.3.4
  • discourse discoursebefore 3.4.0
  • discourse discourse3.4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • discourse discourse

    • stable: <= 3.3.3, beta: <= 3.4.0.beta3, tests-passed: <= 3.4.0.beta3affected

Same product

discourse: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-41163RCE via malicious SNS subscription payload
    45Plan
  • CVE-2025-68662FinalDestination hostname matching allows SSRF protection bypass
    39Monitor
  • CVE-2023-47121Discourse SSRF vulnerability in Embedding
    39Monitor
  • CVE-2026-55674Discourse: Cache poisoning/XSS via color scheme cookies
    37Monitor
  • CVE-2026-53963Discourse: Stored-XSS in 2FA delete confirmation modal
    36Monitor
  • CVE-2024-49765Bypass of Discourse Connect using other login paths if enabled in Discourse
    36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-53963520 days apartDiscourse: Stored-XSS in 2FA delete confirmation modal
    36Monitor
  • CVE-2026-55424520 days apartDiscourse: Topic featured link susceptible to stored XSS
    29Monitor
  • CVE-2024-563280 days apartHTMLi(XSS without CSP) via Onebox urls in Discourse
    24Monitor
  • CVE-2024-5279447 days apartMagnific lightbox susceptible to Cross-site Scripting in Discourse
    24Monitor
  • CVE-2024-47772120 days apartCross-site Scripting (XSS) via chat excerpts when content security policy (CSP) disabled in Discourse
    24Monitor
  • CVE-2025-48062125 days apartDiscourse vulnerable to HTML injection when inviting to topic via email
    24Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records