CyberSecBulletin
CVE-2026-28697NVD status: Analyzed

cms: Improper Neutralization of Special Elements Used in a Template Engine

Published Updated By the CyberSecBulletin desk

CVE-2026-28697 is a critical-severity improper neutralization of special elements used in a template engine vulnerability in cms from Craft CMS, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. Affected cms versions: >= 5.0.0-RC1, < 5.9.0-beta.1; >= 4.0.0-RC1, < 4.17.0-beta.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.19% chance of exploitation within 30 days, higher than 68% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Craft CMS to 4.17.0 or 5.9.0, whichever matches your release line, or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Craft CMScms>= 5.0.0-RC1, < 5.9.0-beta.1; >= 4.0.0-RC1, < 4.17.0-beta.1Not stated
Craft CMSCraft CMSafter 4.0.0 up to, but not including, 4.17.0; after 5.0.0 up to, but not including, 5.9.0; 4.0.0; 5.0.04.17.0, 5.9.0

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.09.4CriticalCNA (github.com)
CVSS 3.19.1CriticalNVD

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Neutralization of Special Elements Used in a Template Engine

The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.

How developers prevent this class of flaw

  • Choose a template engine that offers a sandbox or restricted mode, or at least limits the power of any available expressions, function calls, or commands.
  • Use the template engine's sandbox or restricted mode, if available.

More Improper Neutralization of Special Elements Used in a Template Engine vulnerabilities (CWE-1336)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in cms

All cms vulnerabilities

Recent Improper Neutralization of Special Elements Used in a Template Engine vulnerabilities

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