GHSA-4765-v66x-rqx7 CVE-2026-3113 GO-2026-5112
Mattermost doesn't set permissions on downloaded bulk export
Medium
Go
- Severity
- 5.0 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.13%
- Chance of exploitation in the next 30 days. Higher than 2.73% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-732 Incorrect Permission Assignment for Critical Resource
- Fix
11.4.1- Upgrade github.com/mattermost/mattermost-server to this version or later
Description
Mattermost versions 11.4.x <= 11.4.0, 11.3.x <= 11.3.1, 11.2.x <= 11.2.3, 10.11.x <= 10.11.11 fail to set permissions on downloaded bulk export which allows other local users on the server to be able to read contents of the bulk export. Mattermost Advisory ID: MMSA-2026-00593.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/mattermost/mattermost-server | >= 11.4.0-rc1, < 11.4.1 |
11.4.1 |
| github.com/mattermost/mattermost-server | >= 11.3.0-rc1, < 11.3.2 |
11.3.2 |
| github.com/mattermost/mattermost-server | >= 11.2.0-rc1, < 11.2.4 |
11.2.4 |
| github.com/mattermost/mattermost-server | >= 10.11.0-rc1, < 10.11.12 |
10.11.12 |
| github.com/mattermost/mattermost-server | >= 8.0.0-20260105080200-d27a2195068d, < 8.0.0-20260217110922-b7d4a1f1f59b |
8.0.0-20260217110922-b7d4a1f1f59b |
| github.com/mattermost/mattermost-server | >= 10.11.0-rc1+incompatible, < 10.11.12+incompatible>= 11.2.0-rc1+incompatible, < 11.2.4+incompatible>= 11.3.0-rc1+incompatible, < 11.3.2+incompatible>= 11.4.0-rc1+incompatible, < 11.4.1+incompatible |
10.11.12+incompatible11.2.4+incompatible11.3.2+incompatible11.4.1+incompatible |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/mattermost/mattermost-server Go → 11.4.1
- go
go get github.com/mattermost/mattermost-server@v11.4.1 && go mod tidy
Severity breakdown
CVSS 3.1 5.0
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Weakness
CWE-732: Incorrect Permission Assignment for Critical Resource
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
How to prevent it
- Implementation: When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user) [REF-62], and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.
- Architecture and Design: Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly. This will allow you to maintain more fine-grained control over your resources. [REF-207]
- Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
- Implementation, Installation: During program startup, explicitly set the default permissions or umask to the most restrictive setting possible. Also set the appropriate permissions during program installation. This will prevent you from inheriting insecure permissions from any user who installs or runs the program.
- System Configuration: For all configuration files, executables, and libraries, make sure that they are only readable and writable by the software's administrator.
- Documentation: Do not suggest insecure configuration changes in documentation, especially if those configurations can extend to resources and other programs that are outside the scope of the application.
- Installation: Do not assume that a system administrator will manually change the configuration to the settings that are recommended in the software's manual.
- Operation, System Configuration: Ensure that the software runs properly under the United States Government Configuration Baseline (USGCB) [REF-199] or an equivalent hardening configuration guide, which many organizations use to limit the attack surface and potential risk of deployed software.
- Implementation, System Configuration, Operation: When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to disable public access.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-xmfh-3ccg-c9fx Mattermost has an Incorrect Authorization issue | Low | Also affects github.com/mattermost/mattermost-server |
| GHSA-h998-hxxj-8q83 Mattermost doesn't invalidate cached authentication state for active WebSocket connections during global session revocation | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-g5vr-6pgg-74qv Mattermost doesn't enforce bot-specific permission checks on the user active status endpoint | Low | Also affects github.com/mattermost/mattermost-server |
| GHSA-jqgv-39mg-7c2r Mattermost doesn't authenticate Atlassian Connect installed callbacks, allowing a remote unauthenticated attacker to inject a rogue sharedSecret | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-mxq2-5jpg-7474 Mattermost doesn't validate channel ownership of an existing subscription before applying edits | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-2g8v-grq3-hq2g Mattermost doesn't enforce administrator authorization on the {{setDefaultInstance}} call within the {{/gitlab connect}} command handler | Medium | Also affects github.com/mattermost/mattermost-server |
| GHSA-6hxm-w4hv-vgvw Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints | High | Also affects github.com/mattermost/mattermost-server |
| GHSA-9p44-r552-4wp9 Mattermost doesn't sanitize the Remote Cluster API response on PATCH operations | Medium | Also affects github.com/mattermost/mattermost-server |
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