CVE-2023-1777 Information disclosure in linked message previews
Medium 6.5
Published
Updated
Check this codebase for CVE-2023-1777 and fix it if it is affected.
What it is: CVE-2023-1777 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 31 Mar 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-1777 in the wild and no public exploit code.
Affected packages and fixed versions:
- github.com/mattermost/mattermost-server (Go): affected from 1.4.1-0.20211025164829-f7a8147b825c; fixed in 1.4.1-0.20230301145909-10be118d99a5
- github.com/mattermost/mattermost-server (Go): affected from 1.4.1-0.20211025164829-f7a8147b825c; fixed in 1.4.1-0.20230301145909-10be118d99a5
- github.com/mattermost/mattermost-server (Go): affected from 7.1.0; fixed in 7.1.6
- github.com/mattermost/mattermost-server (Go): affected from 7.1.0; fixed in 7.1.6
- github.com/mattermost/mattermost-server (Go): affected from 7.7.0; fixed in 7.7.2
- github.com/mattermost/mattermost-server (Go): affected from 7.7.0; fixed in 7.7.2
- github.com/mattermost/mattermost-server (Go): affected from 7.8.0; fixed in 7.8.1
- github.com/mattermost/mattermost-server (Go): affected from 7.8.0; fixed in 7.8.1
- mattermost (Bitnami): affected all versions up to 7.7.1; fixed in 7.1.6
- github.com/mattermost/mattermost-server/v6 (Go): affected from 6.0.0-20211025164829-f7a8147b825c; fixed in 6.0.0-20230301145909-10be118d99a5
- github.com/mattermost/mattermost-server/v6 (Go): affected from 6.0.0-20211025164829-f7a8147b825c; fixed in 6.0.0-20230301145909-10be118d99a5
- github.com/mattermost/mattermost-server/v6 (Go): affected from 6.3.0; fixed in 7.1.6
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2023-1777/ (Markdown: https://insights.sbomify.com/CVE-2023-1777/index.md)
Attackers can disclose contents of linked messages by requesting previews via the createPost API, exposing sensitive chat data.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-1777?
CVE-2023-1777 is a medium-severity vulnerability in Mattermost Mattermost Server, published on 31 Mar 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Mattermost allows an attacker to request a preview of an existing message when creating a new message via the createPost API call, disclosing the contents of the linked message.
Which versions are affected by CVE-2023-1777?
13 open source packages ship an affected version, including github.com/mattermost/mattermost-server, mattermost and github.com/mattermost/mattermost-server/v6. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/mattermost/mattermost-server Go | From 1.4.1-0.20211025164829-f7a8147b825c | 1.4.1-0.20230301145909-10be118d99a5 |
github.com/mattermost/mattermost-server Go | From 1.4.1-0.20211025164829-f7a8147b825c | 1.4.1-0.20230301145909-10be118d99a5 |
github.com/mattermost/mattermost-server Go | From 7.1.0 | 7.1.6 |
github.com/mattermost/mattermost-server Go | From 7.1.0 | 7.1.6 |
github.com/mattermost/mattermost-server Go | From 7.7.0 | 7.7.2 |
github.com/mattermost/mattermost-server Go | From 7.7.0 | 7.7.2 |
7 more packages
github.com/mattermost/mattermost-server Go | From 7.8.0 | 7.8.1 |
github.com/mattermost/mattermost-server Go | From 7.8.0 | 7.8.1 |
mattermost Bitnami | All versions to 7.7.1 | 7.1.6 |
github.com/mattermost/mattermost-server/v6 Go | From 6.0.0-20211025164829-f7a8147b825c | 6.0.0-20230301145909-10be118d99a5 |
github.com/mattermost/mattermost-server/v6 Go | From 6.0.0-20211025164829-f7a8147b825c | 6.0.0-20230301145909-10be118d99a5 |
github.com/mattermost/mattermost-server/v6 Go | From 6.3.0 | 7.1.6 |
github.com/mattermost/mattermost-server/v6 Go | From 6.3.0 | 7.1.6 |
Products include Mattermost Mattermost Server.
How do I fix CVE-2023-1777?
Upgrade github.com/mattermost/mattermost-server to a fixed version for your release line: 1.4.1-0.20230301145909-10be118d99a5, 7.1.6, 7.7.2 or 7.8.1.
Is CVE-2023-1777 being exploited?
There is no known exploitation of CVE-2023-1777 in the wild and no public exploit code.
Other vulnerabilities in Mattermost Mattermost Server
- CVE-2025-12419 Account takeover on OAuth/OpenID-enabled servers
- CVE-2025-12421 Account Takeover via Code Exchange Endpoint
- CVE-2025-4981 Path Traversal Leading to RCE by Any Authenticated Mattermost User
- CVE-2025-20051 Arbitrary file read via block duplication in Mattermost Boards
- CVE-2025-25279 Arbitrary file read in Mattermost Boards via import & export board archive
Sources
Also known as BIT-mattermost-2023-1777, GHSA-3wq5-3f56-v5xc.