CVE-2023-5969

Denial of Service via Link Preview in /api/v4/redirect_location

5.3 MediumFix available

Mattermost fails to properly sanitize the request to /api/v4/redirect_location allowing an attacker, sending a specially crafted request to /api/v4/redirect_location, to fill up the memory due to caching large items.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.63%Up 0.6 points since Nov 7, 2023

What each source reports

CVE List Score used 5.3

Denial of Service via Link Preview in /api/v4/redirect_location

Record: CVE-2023-5969
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-400
Updated: 2026-11-02

EUVDEUVD-2023-3048 5.3

Record: EUVD-2023-3048
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated: 2026-11-03

GitHub AdvisoriesGHSA-w496-f5qq-m58j 5.3

Mattermost vulnerable to excessive memory consumption

Mattermost fails to properly sanitize the request to /api/v4/redirect_location allowing an attacker, sending a specially crafted request to /api/v4/redirect_location, to fill up the memory due to caching large items.

Record: GHSA-w496-f5qq-m58j
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-400
Updated: 2026-11-02

NVD 5.3

Record: CVE-2023-5969
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-400
Updated: 2026-11-02

OSV 5.3

Denial of Service via Link Preview in /api/v4/redirect_location

Record: CVE-2023-5969
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-400
Updated: 2026-11-02

OSVGHSA-w496-f5qq-m58j 5.3

Mattermost vulnerable to excessive memory consumption

Record: GHSA-w496-f5qq-m58j
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-400
Updated: 2026-11-02

Affected products

mattermost

Affected packages

Affected packages
Package	Affected	Fixed
`github.com/mattermost/mattermost-server/v6` Go	before 7.8.12	7.8.12
`github.com/mattermost/mattermost/server/v8` Go	8.0.0 up to 8.0.4	8.0.4
`github.com/mattermost/mattermost/server/v8` Go	8.1.0 up to 8.1.3	8.1.3
`github.com/mattermost/mattermost/server/v8` Go	9.0.0 to 9.0.0	9.0.1
`github.com/mattermost/mattermost/server/v8` Go	9.0.0 up to 9.0.1	9.0.1

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-5969 is a medium vulnerability (CVSS 5.3) in Mattermost, published November 6, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.63%, the 50th percentile. Fixed in github.com/mattermost/mattermost-server/v6 7.8.12.