VulnerabilityPublished 11 Aug 2025

CVE-2025-44004: Mattermost Confluence Plugin · Missing Authentication

Affects Mattermost Confluence PluginSource CVE Database V5

Not known to be exploited · CVSS 7.2 High.

Data as of 26 Oct 2026, 14:05 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 10% 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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

Affected software

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

AI-suggested

To mitigate this vulnerability, European organizations should prioritize upgrading the Mattermost Confluence Plugin to version 1.5.0 or later, where the authentication checks are properly enforced. Until the patch is applied, organizations should consider restricting access to the Mattermost API endpoints by implementing network-level controls such as IP whitelisting and firewall rules to limit API access to trusted internal networks only. Additionally, monitoring API usage logs for unusual or unauthorized create channel subscription requests can help detect exploitation attempts early. Organizations should also review and tighten permissions and access controls within both Mattermost and Confluence to minimize the impact of any unauthorized subscriptions. Employing Web Application Firewalls (WAFs) with custom rules to detect and block suspicious API calls targeting the vulnerable endpoint can provide an additional layer of defense. Finally, educating administrators and users about the risks and signs of exploitation can improve incident response readiness.

Description

Mattermost Confluence Plugin version <1.5.0 fails to check the authorization of the user to the Mattermost instance which allows attackers to create a channel subscription without proper authorization via API call to the create channel subscription endpoint.

Impact

For European organizations, this vulnerability poses a risk primarily to the confidentiality and integrity of internal communications and collaboration data. Unauthorized channel subscriptions could expose sensitive Confluence content to unintended audiences, increasing the risk of data leakage. Additionally, attackers could manipulate subscription settings to disrupt normal collaboration processes or gain footholds for further attacks within the Mattermost environment. Organizations in sectors with stringent data protection regulations, such as finance, healthcare, and government, could face compliance violations if sensitive information is exposed. The lack of authentication requirement and remote exploitability mean that attackers can attempt exploitation without prior access, increasing the threat surface. Given Mattermost's growing adoption in European enterprises as a secure communication tool, this vulnerability could affect a broad range of organizations, especially those integrating Mattermost with Confluence for knowledge management and collaboration.

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

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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