Mattermost up to 11.3.0 Burn-on-Read Message insertion of sensitive information into sent data

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.2$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Mattermost up to 11.3.0. The affected element is an unknown function of the component Burn-on-Read Message Handler. This manipulation causes insertion of sensitive information into sent data. This vulnerability is tracked as CVE-2026-2578. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Mattermost up to 11.3.0 and classified as problematic. Affected by this vulnerability is an unknown functionality of the component Burn-on-Read Message Handler. The manipulation with an unknown input leads to a insertion of sensitive information into sent data vulnerability. The CWE definition for the vulnerability is CWE-201. The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. As an impact it is known to affect confidentiality. The summary by CVE is:

Mattermost versions 11.3.x <= 11.3.0 fail to preserve the redacted state of burn-on-read posts during deletion which allows channel members to access unrevealed burn-on-read message contents via the WebSocket post deletion event.. Mattermost Advisory ID: MMSA-2026-00579

The weakness was disclosed by Joshua Rogers. It is possible to read the advisory at mattermost.com. This vulnerability is known as CVE-2026-2578 since 02/16/2026. The exploitation appears to be easy. The attack can be launched remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

Upgrading to version 11.3.1 or 11.4.0 eliminates this vulnerability.

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Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector (Mattermost): 🔒

CVSSv2info

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

Exploitinginfo

Class: Insertion of sensitive information into sent data
CWE: CWE-201 / CWE-200 / CWE-284
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

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: Mattermost 11.3.1/11.4.0

Timelineinfo

02/16/2026 CVE reserved
03/16/2026 +28 days Advisory disclosed
03/16/2026 +0 days VulDB entry created
03/20/2026 +4 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: Joshua Rogers
Status: Confirmed

CVE: CVE-2026-2578 (🔒)
GCVE (CVE): GCVE-0-2026-2578
GCVE (VulDB): GCVE-100-351247

Entryinfo

Created: 03/16/2026 14:50
Updated: 03/20/2026 23:45
Changes: 03/16/2026 14:50 (64), 03/20/2026 23:45 (1)
Complete: 🔍
Cache ID: 216::103

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