Mattermost Plugins up to 11.6.x OpenAI API mattermost.log log file

CVSS Meta Temp Score
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CTI Interest Score
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4.7$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic was found in Mattermost Plugins up to 11.6.x. Affected is an unknown function of the file mattermost.log of the component OpenAI API. Such manipulation leads to log file. This vulnerability is listed as CVE-2026-9699. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Mattermost Plugins up to 11.6.x. It has been rated as problematic. Affected by this issue is an unknown function of the file mattermost.log of the component OpenAI API. The manipulation with an unknown input leads to a log file vulnerability. Using CWE to declare the problem leads to CWE-532. Information written to log files can be of a sensitive nature and give valuable guidance to an attacker or expose sensitive user information. Impacted is confidentiality. CVE summarizes:

Mattermost Plugins versions <=11.6 10.18.11 11.3.6 11.6.5.0 fail to sanitize error responses from the OpenAI API before logging, which allows a user with access to server logs or support packets to obtain a valid or partially reconstructable OpenAI API key via inspection of mattermost.log entries generated during authentication failures. Mattermost Advisory ID: MMSA-2026-00609

The weakness was presented by Edgar Bellot Micó. The advisory is available at mattermost.com. This vulnerability is handled as CVE-2026-9699 since 05/27/2026. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are necessary for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1592 by the MITRE ATT&CK project.

By approaching the search of inurl:mattermost.log it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 10.11.19, 11.5.7, 11.6.4 or 11.7.0 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.7
VulDB Meta Temp Score: 4.7

VulDB Base Score: 2.7
VulDB Temp Score: 2.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.8
CNA Vector (Mattermost): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Log file
CWE: CWE-532 / CWE-200 / CWE-284
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Google Hack: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Plugins 10.11.19/11.5.7/11.6.4/11.7.0

Timelineinfo

05/27/2026 CVE reserved
06/26/2026 +30 days Advisory disclosed
06/26/2026 +0 days VulDB entry created
06/26/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: Edgar Bellot Micó
Status: Confirmed

CVE: CVE-2026-9699 (🔒)
GCVE (CVE): GCVE-0-2026-9699
GCVE (VulDB): GCVE-100-374318

Entryinfo

Created: 06/26/2026 19:11
Changes: 06/26/2026 19:11 (67)
Complete: 🔍
Cache ID: 216::103

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