How severe is CVE-2023-1775?

CVE-2023-1775 has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-1775?

CVE-2023-1775 affects the following packages: github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server (Go), github.com/mattermost/mattermost-server/v5 (Go), github.com/mattermost/mattermost-server/v6 (Go). Ecosystems affected: Go.

How do I fix CVE-2023-1775?

Update github.com/mattermost/mattermost-server to 7.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-1775 is resolved across your whole dependency graph.

How do I detect CVE-2023-1775 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-1775 if there is no patch (or I can't update yet)?

Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Is CVE-2023-1775 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-1775 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-1775?

CVE-2023-1775 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 46th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-1775?

CVE-2023-1775 is classified as Information Exposure (CWE-200), CWE-668 (CWE-668). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-1775 published, and has it been updated?

CVE-2023-1775 was published on March 31, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2023-1775 — mattermost-server

MEDIUM

CVE-2023-1775 is a medium-severity (CVSS 4.3) Information Exposure vulnerability in github.com/mattermost/mattermost-server. A fix is available for github.com/mattermost/mattermost-server — see the affected versions and patch details below.

Unsanitized events sent over Websocket to regular users in a High Availability environment

Also known asBIT-mattermost-2023-1775GHSA-8jhh-3jf2-pfwr

Published

Mar 31, 2023

Updated

Oct 28, 2026

Affected

5 pkgs

Patched

5 / 5

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-1775.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs46th percentile — riskier than 46% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

5 pkgs affected

🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost-server🐹github.com/mattermost/mattermost-server/v5🐹github.com/mattermost/mattermost-server/v6

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

When running in a High Availability configuration, Mattermost fails to sanitize some of the user_updated and post_deleted events broadcast to all users, leading to disclosure of sensitive information to some of the users with currently connected Websocket clients.

Issue Identifier: MMSA-2023-00138

Affected Packages

5 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/mattermost/mattermost-server`	≥ 3.3.0&&< 7.1.6	7.1.6`go get github.com/mattermost/mattermost-server@v7.1.6`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 7.7.0&&< 7.7.2	7.7.2`go get github.com/mattermost/mattermost-server@v7.7.2`
🐹Go	`github.com/mattermost/mattermost-server`	≥ 7.1.0&&< 7.1.6	7.1.6`go get github.com/mattermost/mattermost-server@v7.1.6`
🐹Go	`github.com/mattermost/mattermost-server/v5`	≥ 5.0.0&&< 7.1.6	7.1.6`go get github.com/mattermost/mattermost-server/v5@v7.1.6`
🐹Go	`github.com/mattermost/mattermost-server/v6`	≥ 6.0.0&&< 7.1.6	7.1.6`go get github.com/mattermost/mattermost-server/v6@v7.1.6`

Affected Products

1 product · 2 configurations

Application

mattermost servermattermost

< 7.1.6

1 version

7.7.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/mattermost/mattermost-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/mattermost/mattermost-server to 7.1.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-1775 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

When running in a High Availability configuration, Mattermost fails to sanitize some of the `user_updated` and` post_deleted` events broadcast to all users, leading to disclosure of sensitive information to some of the users with currently connected Websocket clients. [Issue Identifier](https://mattermost.com/security-updates/): MMSA-2023-00138

O3 Security · Impact-Aware SCA

Is CVE-2023-1775 in your dependencies?

Find it across Go, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

4.3/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

None

Raw vector

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

CWE Classification

CWE-200Information Exposure CWE-668CWE-668

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Mar 31, 2023

Last updated

Oct 28, 2026

Identifiers

CVE-2023-1775

GHSA-8jhh-3jf2-pfwr

BIT-mattermost-2023-1775

References

Advisorygithub.com · CVE 2023 1775.json Advisorynvd.nist.gov · CVE 2023 1775 Webmattermost.com · security updates Webmattermost.com · security updates Packagegithub.com.mattermost · mattermost server

Related vulnerabilities

This CVE is medium severity; 6 of 8 other CVEs affecting mattermost-server are rated as high or higher (top: high).

CVE-2026-5139CVE-2026-8074CVE-2026-9162CVE-2026-6673CVE-2026-6062CVE-2026-8823CVE-2026-6046CVE-2026-7387

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 28, 2026

CVE-2023-1775 — mattermost-server

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2023-1775 in your dependencies?