VulnerabilityPublished 25 Mar 2026

CVE-2026-3211: Drupal Theme Negotiation by Rules · Cross-Site Request Forgery (CSRF)

Affects Drupal Theme Negotiation by RulesSource CVE Database V5

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Not known to be exploited · CVSS 4.3 Medium : upgrade to 1.2.1 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

4.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.2.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Drupal Theme Negotiation by Rules to 1.2.1.

Affected software

Product	Affected	Fixed in
DrupalTheme Negotiation by Rules	Affected <1.2.1	Fixed in 1.2.1

AI-suggested

Organizations should immediately verify if they use the Theme Negotiation by Rules module and identify affected versions. The primary mitigation is to upgrade the module to version 1.2.1 or later once available, as this will include proper CSRF protections. If you cannot patch yet, administrators should restrict user roles and permissions to minimize the number of users able to perform theme negotiation actions. Implementing web application firewalls (WAFs) with rules to detect and block CSRF attack patterns can provide temporary protection. Educating users about phishing and social engineering risks is critical since exploitation requires user interaction. Additionally, site administrators should monitor logs for suspicious requests that could indicate attempted CSRF attacks. Employing Drupal’s built-in security modules and ensuring all modules follow secure coding practices will reduce exposure. Regular security audits and vulnerability scanning focused on CSRF and related web vulnerabilities are recommended.

Description

Cross-Site Request Forgery (CSRF) vulnerability in Drupal Theme Negotiation by Rules allows Cross Site Request Forgery.This issue affects Theme Negotiation by Rules: from 0.0.0 before 1.2.1.

Impact

The primary impact of this vulnerability is on the integrity and potentially the availability of Drupal sites using the Theme Negotiation by Rules module. Attackers can cause authenticated users to unknowingly change theme settings, which may disrupt site appearance or user experience, damaging organizational reputation. In some scenarios, altered themes could be used to inject malicious content or facilitate phishing attacks, indirectly impacting confidentiality and user trust. Since the vulnerability requires an authenticated user, the attack surface is limited to users with login privileges, but many Drupal sites have broad user bases including administrators or editors, increasing risk. The lack of known exploits reduces immediate threat but does not eliminate the risk of targeted attacks. Organizations worldwide relying on Drupal for critical web infrastructure could face defacement, user confusion, or indirect compromise. The vulnerability does not directly lead to remote code execution or data leakage but can be a stepping stone in multi-stage attacks.

CWE-352Cross-Site Request Forgery (opens in a new tab)
Compound weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #3OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation
Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
Architecture and Design
Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).
OWASP Cheat Sheets
REST Assessment (opens in a new tab)
REST Security (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
Insecure Direct Object Reference Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V13.2.3 (opens in a new tab)
V4.2.2 (opens in a new tab)
V13.3.2 (opens in a new tab)
Attack patterns
JSON Hijacking (aka JavaScript Hijacking) (opens in a new tab)
Cross-Domain Search Timing (opens in a new tab)
Cross Site Identification (opens in a new tab)
Cross Site Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

drupal.org/sa-contrib-2026-012 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Mar 2026, 16:03 UTC

WeaknessesCWE-352

Technical details

References

Community reviews

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