Mattermost up to 10.11.11/11.2.3/11.3.1/11.4.0 Zip data amplification

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic was found in Mattermost up to 10.11.11/11.2.3/11.3.1/11.4.0. Affected is an unknown function of the component Zip Handler. The manipulation results in data amplification. This vulnerability is reported as CVE-2026-3114. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic has been found in Mattermost up to 10.11.11/11.2.3/11.3.1/11.4.0. Affected is an unknown function of the component Zip Handler. The manipulation with an unknown input leads to a data amplification vulnerability. CWE is classifying the issue as CWE-409. The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. This is going to have an impact on availability. CVE summarizes:

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 validate decompressed archive entry sizes during file extraction which allows authenticated users with file upload permissions to cause a denial of service via crafted zip archives containing highly compressed entries (zip bombs) that exhaust server memory.. Mattermost Advisory ID: MMSA-2026-00598

The weakness was disclosed by winfunc. The advisory is available at mattermost.com. This vulnerability is traded as CVE-2026-3114 since 02/24/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 10.11.12, 11.2.4, 11.3.2, 11.4.1 or 11.5.0 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector (Mattermost): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Data amplification
CWE: CWE-409 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Mattermost 10.11.12/11.2.4/11.3.2/11.4.1/11.5.0

Timelineinfo

02/24/2026 CVE reserved
03/26/2026 +30 days Advisory disclosed
03/26/2026 +0 days VulDB entry created
03/26/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mattermost.com
Researcher: winfunc
Status: Confirmed

CVE: CVE-2026-3114 (🔒)
GCVE (CVE): GCVE-0-2026-3114
GCVE (VulDB): GCVE-100-353682

Entryinfo

Created: 03/26/2026 19:02
Changes: 03/26/2026 19:02 (64)
Complete: 🔍
Cache ID: 216::103

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