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Fencer Intel
medium 4.3

CVE-2018-21252 json

An issue was discovered in Mattermost Server before 5.2, 5.1.1, 5.0.3, and 4.10.3.

published 6y ago modified 4mo ago also EUVD-2018-13767

cvss
4.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

An issue was discovered in Mattermost Server before 5.2, 5.1.1, 5.0.3, and 4.10.3. Attackers could use multiple e-mail addresses to bypass a domain-based policy for signups.

Patch / fix

  • mattermost mattermost_server 4.10.3, 5.0.3, 5.1.1

Is CVE-2018-21252 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N

Classification

Weakness
  • CWE-732 Incorrect Permission Assignment for Critical Resource

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.