CVE-2026-10556
- Source
- https://cve.org/CVERecord?id=CVE-2026-10556
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-10556.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-10556
- Downstream
- Published
- 2026-09-14T10:46:01Z
- Modified
- 2026-10-09T02:49:19Z
- Severity
-
- 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
- Summary
- Unauthenticated webhook request with null notification entry could crash the Microsoft Calendar plugin.
- Details
-
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to validate null entries in Microsoft Graph webhook notification payloads, which allows an unauthenticated attacker to crash the Microsoft Calendar plugin process and deny calendar integration service to all users on the instance via a crafted {{POST}} request to the public webhook endpoint.. Mattermost Advisory ID: MMSA-2026-00693
- Database specific
{ "cna_assigner": "Mattermost", "cwe_ids": [ "CWE-754" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/10xxx/CVE-2026-10556.json", "unresolved_ranges": [ { "extracted_events": [ { "introduced": "11.8.0" }, { "last_affected": "11.8.4" }, { "introduced": "11.7.0" }, { "last_affected": "11.7.7" }, { "introduced": "10.11.0" }, { "last_affected": "10.11.22" }, { "introduced": "11.9.0" }, { "last_affected": "11.9.0" } ], "source": "AFFECTED_FIELD" } ] }- References
Affected packages
Git / github.com/mattermost/mattermost
Affected ranges
- Type
- GIT
- Repo
- https://github.com/mattermost/mattermost
- Events
-
IntroducedFixedIntroducedFixedIntroducedFixedIntroducedFixed
- Database specific
-
Show details
{ "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "extracted_events": [ { "introduced": "10.11.0" }, { "fixed": "10.11.23" }, { "introduced": "11.7.0" }, { "fixed": "11.7.8" }, { "introduced": "11.8.0" }, { "fixed": "11.8.5" }, { "introduced": "11.9.0" }, { "fixed": "11.9.1" } ], "source": "CPE_RANGE" }
Affected versions
@mattermost/client@10.*
@mattermost/client@10.11.0
@mattermost/client@11.*
@mattermost/client@11.7.0
@mattermost/client@11.8.0
@mattermost/client@11.9.0
@mattermost/shared@11.*
@mattermost/shared@11.7.0
@mattermost/shared@11.8.0
@mattermost/shared@11.9.0
@mattermost/types@10.*
@mattermost/types@10.11.0
@mattermost/types@11.*
@mattermost/types@11.7.0
@mattermost/types@11.8.0
@mattermost/types@11.9.0
mattermost-redux@10.*
mattermost-redux@10.11.0
mattermost-redux@11.*
mattermost-redux@11.7.0
mattermost-redux@11.8.0
mattermost-redux@11.9.0
v10.*
v10.11.0
v10.11.0-rc3
v10.11.1
v10.11.1-rc1
v10.11.10
v10.11.11
v10.11.11-rc1
v10.11.11-rc2
v10.11.12
v10.11.13
v10.11.13-rc1
v10.11.14
v10.11.14-rc1
v10.11.15
v10.11.15-rc1
v10.11.16
v10.11.17
v10.11.18
v10.11.19
v10.11.19-rc1
v10.11.2
v10.11.2-rc1
v10.11.2-rc2
v10.11.20
v10.11.21
v10.11.22
v10.11.3
v10.11.4
v10.11.4-rc1
v10.11.4-rc2
v10.11.4-rc3
v10.11.5
v10.11.6
v10.11.7
v10.11.8
v10.11.9
v10.11.9-rc1
v11.*
v11.7.0
v11.7.1
v11.7.2
v11.7.3
v11.7.4
v11.7.5
v11.7.5-rc1
v11.7.6
v11.7.7
v11.8.0
v11.8.0-rc5
v11.8.1
v11.8.2
v11.8.3
v11.8.4
v11.9.0