CVE-2025-54940VulnerabilityPublished 8 Aug 2025

CVE-2025-54940: Advanced Custom Fields (WordPress plugin) · Code Injection

Affects Advanced Custom Fields (WordPress plugin)Source CVE Database V5

Not known to be exploited · CVSS 3.4 Low : upgrade to 6.4.3 when convenient.

Data as of 26 Oct 2026, 07:57 UTC

CVSS 3.0 base score

3.4Low

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 6.4.3

CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: Required
Scope: Changed
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: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
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 8 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-26.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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 Advanced Custom Fields (WordPress plugin) to 6.4.3.

Affected software

Product	Affected	Fixed in
WPEngine, Inc. Advanced Custom Fields	Affected <6.4.3	Fixed in 6.4.3

AI-suggested

1. Upgrade the Advanced Custom Fields plugin to version 6.4.3 or later immediately to apply the official fix addressing this vulnerability. 2. Restrict administrative and high-privilege user access to trusted personnel only, and enforce strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of privilege abuse. 3. Conduct user training and awareness programs to reduce the risk of social engineering attacks that could trick privileged users into interacting with malicious content. 4. Implement Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of injected HTML. 5. 6. Use web application firewalls (WAF) with rules tailored to detect and block suspicious HTML injection attempts targeting WordPress plugins. 7. Employ security scanning tools that can detect HTML injection and other content manipulation vulnerabilities in web applications. 8. Review and harden user input sanitization and output encoding practices in custom code interacting with the ACF plugin to minimize injection risks.

Description

An HTML injection vulnerability exists in WordPress plugin "Advanced Custom Fields" prior to 6.4.3. If this vulnerability is exploited, crafted HTML code may be rendered and page display may be tampered.

Impact

For European organizations, the impact of CVE-2025-54940 is primarily related to the integrity of web content and user trust. Organizations relying on WordPress sites with the Advanced Custom Fields plugin are at risk of having their page displays tampered with if an attacker can gain high-level access and trick users into interaction. This could lead to misinformation, defacement, or manipulation of displayed data, which can harm brand reputation and user confidence. Although the vulnerability does not directly compromise confidentiality or availability, the integrity impact can indirectly affect business operations, especially for e-commerce, government, or media websites where content accuracy is critical. The requirement for high privileges and user interaction limits the threat to insiders or targeted phishing/social engineering campaigns. European organizations with strict compliance requirements around data integrity and user trust, such as financial institutions, healthcare providers, and public sector entities, should consider this vulnerability a moderate risk. Additionally, the potential for scope change means that the vulnerability could affect multiple components or plugins interacting with ACF, increasing the attack surface. Since no known exploits are reported in the wild, the immediate risk is low, but proactive mitigation is recommended to prevent future exploitation.

References

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