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Fencer Vulns
critical 9.1

CVE-2026-28697 json

Craft Affected by Authenticated RCE via "craft.app.fs.write()" in Twig Templates

published 2026-03-03 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-9447 , GHSA-v47q-jxvr-p68x

cvss
9.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

Craft is a content management system (CMS). Prior to 4.17.0-beta.1 and 5.9.0-beta.1, an authenticated administrator can achieve Remote Code Execution (RCE) by injecting a Server-Side Template Injection (SSTI) payload into Twig template fields (e.g., Email Templates). By calling the craft.app.fs.write() method, an attacker can write a malicious PHP script to a web-accessible directory and subsequently access it via the browser to execute arbitrary system commands. This vulnerability is fixed in 4.17.0-beta.1 and 5.9.0-beta.1.

Patch / fix

  • packagist craftcms/cms 4.17.0-beta.1, 5.9.0-beta.1
  • craftcms craft_cms 4.17.0-beta.1, 5.9.0-beta.1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
8 mo ago

Exploit prediction

1.19% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/craftcms/cms/security/advisories/GHSA-v47q-jxvr-p68x referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA 4.0 9.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist craftcms/cms
>=5.0.0-RC1, <5.9.0-beta.1
>=4.0.0-RC1, <4.17.0-beta.1
5.9.0-beta.1
4.17.0-beta.1

Affected products

  • craftcms cms

Classification

Weakness
  • CWE-1336 Improper Neutralization of Special Elements Used in a Template Engine

References

Sources

Fencer Vulns 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.