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CVE-2017-18906

24
FAUCET Score

CVE-2017-18906 describes an account takeover vulnerability in Mattermost Server versions prior to 4.0.0, 3.10.2, and 3.9.2, specifically when Single Sign-On OAuth2 is utilized. This flaw, rated 8.1 HIGH on the CVSS scale, allows an authenticated attacker to claim another user's account with low attack complexity, leading to high confidentiality and integrity impacts. There is no evidence of active exploitation, publicly available exploit code, or inclusion in the KEV catalog, though it has received some community discussion and media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 3.9.2CPE matchmatch criteria
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
>= 3.10.0, < 3.10.2CPE matchmatch criteria
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.1HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.79%
Probability of exploitation in next 30 days
EPSS Percentile
52.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0079 is in the 46th percentile among its peer group of 17,829 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

gopatch availablevia ghsa
Product: github.com/mattermost/mattermost-serverFixed in: 3.9.2-0.20170714134023-b17fca0d5ee7
gopatch availablevia ghsa
Product: github.com/mattermost/mattermost-serverFixed in: 3.10.2

Vendor Advisories (1)

goGHSA-fpcr-4rr5-hpcphigh

Mattermost Server vulnerable to user account takeover when Single Sign-On OAuth2 is used

May 24, 2022

References

mattermost.com / security-updates
Vendor Advisory