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CVE-2021-37865

Server-side Denial of Service while processing a specifically crafted GIF file

MEDIUM
5.7
CVSS Score
Published: January 18, 2022 at 04:51 PM UTC
Updated: June 17, 2026 at 04:01 AM UTC
1 product affected across 1 vendorMattermost

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Severity
MEDIUM5.7
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

Description

Mattermost 6.2 and earlier fails to sufficiently process a specifically crafted GIF file when it is uploaded while drafting a post, which allows authenticated users to cause resource exhaustion while processing the file, resulting in server-side Denial of Service.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Mattermost· Mattermost
95%
v ≤ 6.2
Vendor states this is fixed in 5.37.6 (unaffected)
Vendor states this is fixed in 5.39.3 (unaffected)
Vendor states this is fixed in 6.0.4 (unaffected)
Vendor states this is fixed in 6.1.1 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

x_refsource_MISCPermissions Required
Source: [email protected]
https://hackerone.com/reports/1428260
x_refsource_MISCVendor Advisory
Source: [email protected]
https://mattermost.com/security-updates/

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.7MEDIUM[email protected]
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-400

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