# CVE-2020-14457: GO-2023-1939 - Mattermost Server Sensitive Data Exposure in github.com/mattermost/mattermost

Source: https://junglewise.ai/threats/cve-2020-14457-mattermost-server-sensitive-data-exposure  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-08-20  
License: CC BY 4.0 with a link back

CVE-2020-14457 · Severity: low · CVSS 3.1 · Published 2024-08-20

Mattermost Server Sensitive Data Exposure in github.com/mattermost/mattermost

Technologies: [github.com/mattermost/mattermost (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost), [github.com/mattermost/mattermost-server (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost-server), [github.com/mattermost/mattermost-server/v5 (Go)](https://junglewise.ai/threats/technologies/github-com-mattermost-mattermost-server-v5). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2020-14457 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2020-14457 being exploited in the wild.

**How severe is CVE-2020-14457?** Low severity, with a CVSS score of 3.1, published 20 August 2024.

**Which products and versions are affected?** github.com/mattermost/mattermost (Go) SEMVER:introduced=0; github.com/mattermost/mattermost-server (Go) SEMVER:introduced=0; github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0,fixed=5.20.0.

**Is there a fix for CVE-2020-14457?** Yes. github.com/mattermost/mattermost-server/v5 (Go): upgrade to 5.20.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2020-14457?** Check whether you run github.com/mattermost/mattermost (Go), github.com/mattermost/mattermost-server (Go) or github.com/mattermost/mattermost-server/v5 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/mattermost/mattermost-server/v5 (Go): upgrade to 5.20.0 or later

  ```sh
  go get github.com/mattermost/mattermost-server/v5@v5.20.0
  ```


## Affected products

- github.com/mattermost/mattermost (Go) SEMVER:introduced=0
- github.com/mattermost/mattermost-server (Go) SEMVER:introduced=0
- github.com/mattermost/mattermost-server/v5 (Go) SEMVER:introduced=0,fixed=5.20.0

## Identifiers

- CVE-2020-14457
- GHSA-j2h2-cvwh-cr64
- GO-2023-1939

## Related threats

- [Mattermost doesn't validate decompressed archive entry sizes during file extraction](https://junglewise.ai/threats/cve-2026-3114-mattermost-doesn-t-validate-decompressed-archive-entry-sizes)
- [Mattermost allows authenticated guest users to enumerate user IDs outside their allowed visibility scope](https://junglewise.ai/threats/cve-2026-3115-mattermost-allows-authenticated-guest-users-to-enumerate-user-ids)
- [GO-2026-5629 - Mattermost doesn't properly validate CSRF tokens in github.com/mattermost/mattermost-server](https://junglewise.ai/threats/cve-2026-27659-mattermost-doesn-t-properly-validate-csrf-tokens)
- [GO-2026-5495 - Mattermost doesn't validate CSRF tokens on an authentication endpoint in github.com/mattermost/mattermost-server](https://junglewise.ai/threats/cve-2026-28741-mattermost-doesn-t-validate-csrf-tokens-on-an-authentication)
- [Mattermost allows attackers to take over arbitrary user accounts via overly permissive substring matching flaw](https://junglewise.ai/threats/cve-2026-27656-mattermost-allows-attackers-to-take-over-arbitrary-user-accounts)