vulnerability / NVI-00007758 / Revision 4
Grav CMS vulnerable to stored XSS via Markdown media attribute() action
GitHub lists this reviewed advisory for getgrav/grav. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
4.8 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
4.8 MEDIUM (3.1)
nvd@nist.gov severity; no combined Null risk score.
6.9 MEDIUM (4.0)
security-advisories@github.com severity; no combined Null risk score.
0.420%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.36394. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
getgrav/grav
source listed< 2.0.0-beta.2
### Summary An authenticated user with page editing permissions can inject an executable JavaScript event-handler attribute into rendered image HTML through Grav's Markdown media action syntax. The issue is caused by Markdown image query parameters being converted into callable media actions. The public `attribute()` media method can be reached this way, allowing an editor to set an arbitrary HTML attribute name and value on the generated image element. For example, this Markdown: ```markdown !Quarterly market overview) ``` is rendered as an image tag containing an executable `onload` handler: ```html ``` This results in stored XSS when another user views the affected page. In a multi-user Grav installation, a lower-privileged page editor could use this to target administrators or reviewers who preview or view editor-controlled content. Tested versions: - Grav CMS: 1.7.49.5 - Admin Plugin: 1.10.49.1 Suggested classification: - CWE-79: Improper Neutralization of Input During Web Page Gene
getgrav/grav
source listedECOSYSTEM: introduced 0; fixed 2.0.0-beta.2
### Summary An authenticated user with page editing permissions can inject an executable JavaScript event-handler attribute into rendered image HTML through Grav's Markdown media action syntax. The issue is caused by Markdown image query parameters being converted into callable media actions. The public `attribute()` media method can be reached this way, allowing an editor to set an arbitrary HTML attribute name and value on the generated image element. For example, this Markdown: ```markdown !Quarterly market overview) ``` is rendered as an image tag containing an executable `onload` handler: ```html ``` This results in stored XSS when another user views the affected page. In a multi-user Grav installation, a lower-privileged page editor could use this to target administrators or reviewers who preview or view editor-controlled content. Tested versions: - Grav CMS: 1.7.49.5 - Admin Plugin: 1.10.49.1 Suggested classification: - CWE-79: Improper Neutralization of Input During Web Page Gene
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
- vendor patch
The original advisory lists fixed boundaries 2.0.0-beta.2 for getgrav/grav. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-r7fx-8g49-7hhr ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- GHSA-r7fx-8g49-7hhr ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-42841 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-42841 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 4 ·
Source facts changed; compare the preserved prior revision.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.