CVE-2025-54478VulnerabilityPublished 11 Aug 2025

CVE-2025-54478: Mattermost Confluence Plugin · Missing Authentication

Affects Mattermost Confluence PluginSource CVE Database V5

Not known to be exploited · CVSS 7.2 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.2High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 15% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: Low
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: None: The vulnerable system can be exploited without any interaction from any user.
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to 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 11 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 2026-10-25.

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

Affected software

Product	Affected	Fixed in
Mattermost Mattermost Confluence Plugin	Affected =0	Fixed in–

AI-suggested

To mitigate CVE-2025-54478, European organizations should immediately upgrade the Mattermost Confluence Plugin to version 1.5.0 or later, where proper authentication enforcement has been implemented. Until the patch is applied, organizations should restrict network access to the Mattermost API endpoints by implementing firewall rules or API gateway controls that limit access to trusted users and IP ranges. Monitoring and logging API calls related to channel subscription edits should be enhanced to detect any unauthorized or anomalous activity promptly. Organizations should also review and tighten Mattermost instance permissions and audit existing channel subscriptions for unauthorized changes. Employing multi-factor authentication (MFA) on Mattermost user accounts can reduce the risk of compromised credentials being used to exploit related vulnerabilities. Additionally, security teams should conduct penetration testing focused on API endpoints to identify any other missing authentication or authorization controls. Finally, raising user awareness about potential phishing or social engineering attempts that could leverage altered subscription settings will help mitigate secondary risks.

Description

Mattermost Confluence Plugin version <1.5.0 fails to enforce authentication of the user to the Mattermost instance which allows unauthenticated attackers to edit channel subscriptions via API call to the edit channel subscription endpoint.

Impact

For European organizations, the impact of CVE-2025-54478 can be significant, especially for those relying on Mattermost integrated with Confluence for internal communications and knowledge sharing. Unauthorized editing of channel subscriptions can lead to unintended disclosure of sensitive project or organizational information if attackers subscribe themselves or others to channels they should not access. It can also disrupt communication flows by unsubscribing legitimate users or altering notification settings, thereby impacting operational efficiency and incident response capabilities. Given the collaborative nature of these platforms, such unauthorized changes could facilitate further social engineering or lateral movement within the organization. Additionally, organizations subject to strict data protection regulations such as GDPR may face compliance risks if unauthorized access leads to personal data exposure. The vulnerability's network accessibility and lack of required authentication make it easier for remote attackers to exploit without insider access, increasing the threat surface. Although availability is not directly impacted, the integrity and confidentiality concerns are sufficient to warrant urgent remediation in environments where Mattermost and Confluence are critical to business operations.

CWE-306Missing Authentication for Critical Function (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #21OWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Architecture and Design
Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Architecture and Design
Where possible, avoid implementing custom, "grow-your-own" authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.2.3 (opens in a new tab)
V1.2.2 (opens in a new tab)
V1.2.4 (opens in a new tab)
Attack patterns
Choosing Message Identifier (opens in a new tab)
Force the System to Reset Values (opens in a new tab)
Using Unpublished Interfaces or Functionality (opens in a new tab)
Cross Site Request Forgery (opens in a new tab)
Communication Channel Manipulation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

mattermost.com/security-updates (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Aug 2025, 19:33 UTC

WeaknessesCWE-306

Technical details

References

Community reviews

Related threats