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Fencer Intel
medium 6.5

CVE-2025-20630 json

Mobile crash via object that can't be cast to String in Attachment Field

published last yr. modified 4mo ago also EUVD-2025-2180

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Mattermost Mobile versions <=2.22.0 fail to properly handle posts with attachments containing fields that cannot be cast to a String, which allows an attacker to cause the mobile to crash via creating and sending such a post to a channel.

Patch / fix

  • Mattermost Mattermost 2.23.0

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Mattermost Mattermost

Classification

Weakness
  • CWE-1287 Improper Validation of Specified Type of Input

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.