Skip to content
Fencer Intel
medium 4.8

CVE-2026-55890 json

Grav: Stored CSS injection via Markdown image ?style=… reaches MediaObjectTrait::style()

published 4mo ago modified 17d ago also EUVD-2026-42946 , GHSA-pmf8-g7c8-7v54

cvss
4.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

Grav is a file-based Web platform. Prior to 2.0.0-rc.9, Grav's incomplete fix for stored XSS through the Markdown media attribute action (CVE-2026-42841) leaves the sibling MediaObjectTrait::style method reachable through the same Markdown excerpt-action pipeline, allowing an editor to save Markdown image style parameters that are written into the rendered img style attribute without sanitization. This issue is fixed in version 2.0.0-rc.9.

Patch / fix

  • packagist getgrav/grav 2.0.0-rc.9
  • getgrav grav 2.0.0-rc.9
  • getgrav grav_cms 2.0.0-rc.9

Is CVE-2026-55890 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/getgrav/grav/security/advisories/GHSA-pmf8-g7c8-7v54 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist getgrav/grav
<2.0.0-rc.9
2.0.0-rc.9

Affected products

  • getgrav grav

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.