VulnerabilityPublished 19 Dec 2025

CVE-2025-66911: turms · CVE-2025-66911 is a broken access control

Affects turmsSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within 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 19 Dec 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 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
GitHubturms-im/turms`pkg:github/turms-im/turms`Other threats	Affected =0.10.0-SNAPSHOT	Fixed in–

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AI-suggested

To mitigate this vulnerability, organizations should first verify if they are running affected versions of Turms IM Server (v0.10.0-SNAPSHOT or earlier). Immediate steps include restricting access to the user online status query API to only highly trusted roles or administrators through network segmentation or API gateway policies. Implement additional authorization checks at the application layer to ensure users can only query their own status or those they are explicitly permitted to view. Monitoring and logging access to this functionality can help detect anomalous queries indicative of exploitation attempts. If patches or updates become available from the vendor, prioritize their deployment. In the absence of patches, consider disabling or limiting the affected functionality temporarily. Educate users on credential security to reduce risk from compromised accounts. Finally, conduct regular access control audits and penetration testing focused on authorization mechanisms to prevent similar issues.

Description

CVE-2025-66911 is a broken access control vulnerability in Turms IM Server v0.10.0-SNAPSHOT and earlier. It allows any authenticated user to query sensitive information such as online status, device details, and login timestamps of arbitrary users without proper authorization. The vulnerability resides in the handleQueryUserOnlineStatusesRequest() method in UserServiceController.java. Exploitation requires authentication but no user interaction and can lead to significant confidentiality breaches. The CVSS score is 6.5 (medium severity) with network attack vector and low attack complexity. There are no known exploits in the wild yet.

Impact

For European organizations, the primary impact is the unauthorized disclosure of sensitive user metadata such as online status, device details, and login timestamps. This can lead to privacy violations, regulatory non-compliance (e.g., GDPR), and potential reputational damage. Attackers with valid credentials could map user activity patterns, infer organizational structures, or identify high-value targets for further attacks. While the vulnerability does not allow direct data modification or service disruption, the confidentiality breach alone is significant, especially in sectors handling sensitive communications such as finance, healthcare, or government. Organizations relying on Turms IM Server for internal or customer communications may face increased risk of insider threats or external attackers leveraging compromised credentials. The absence of known exploits provides a window for remediation, but the medium severity score warrants timely action to prevent escalation.

CWE-639Authorization Bypass Through User-Controlled Key (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #24OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
Architecture and Design
For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
Architecture and Design · Implementation
Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
Architecture and Design
Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.
OWASP Cheat Sheets
Access Control (opens in a new tab)
Authorization Testing Automation (opens in a new tab)
Cross-Site Request Forgery Prevention (opens in a new tab)
Insecure Direct Object Reference Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V4.1.2 (opens in a new tab)
V4.2.1 (opens in a new tab)
V8.3.8 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-284Improper Access Control (opens in a new tab)
Pillar weaknessCWE Top 25 (2025): #19OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Operation
Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
Third Party Javascript Management (opens in a new tab)
Virtual Patching (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V1.4.4 (opens in a new tab)
V1.4.5 (opens in a new tab)
V1.10.1 (opens in a new tab)
Attack patterns
Embedding Scripts within Scripts (opens in a new tab)
Modification of Windows Service Configuration (opens in a new tab)
Malicious Root Certificate (opens in a new tab)
Intent Spoof (opens in a new tab)
WebView Exposure (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Dec 2025, 15:23 UTC

WeaknessesCWE-639, CWE-284

Technical details

References

Community reviews

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