VulnSocial

CVE-2026-27769Disclosure(mattermost / mattermost_server)

LOWCVSS 2.7 · LOW

Signal is active with 2 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

Mattermost versions 10.11.x <= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server connected using the Conntexted Workspaces feature to change the displayed status of local users via the Connected Workspaces API.. Mattermost Advisory ID: MMSA-2026-00603

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0.0/ 10 priority

Sources & remediation

Vendor / third-party advisories
Weakness type (CWE)
CWE-862

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • mattermost_server

Threat summary

  • 3 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Technical details provided in 3 signals
  • Disclosure: 3 classified signals
  • Peaked at 2 mentions on most recent observed day (2026-04-16)
  • 3 total mentions across 2 days

Affected systems

Vendors
mattermost
Products
mattermost_server

Deep dive

Activity timeline3 mentions / 2d
01122Mentions · 2026-04-15: 1Mentions · 2026-04-16: 2Technical Details · 2026-04-15: 1Technical Details · 2026-04-16: 204-1504-16
Signal classification1 categories
Disclosure
3100.0%
Referenced assets3 URLs
Classification over time
DateTotalLabels
2026-04-151
Disclosure1
2026-04-162
Disclosure2
Full discourse3 posts
  • Infoflowcloud@infoflowcloud
    Disclosure

    🚨*CVE* CVE-2026-27769 Mattermost versions 10.11.x &lt;= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server … https://www.cve.org/CVERecord?id=CVE-2026-27769 ----- Traducción: CVE-2026-27769 Las… http://infoflow.cloud`

    Post summary

    The tweet announces CVE‑2026‑27769, explaining that this vulnerability in Mattermost versions 10.11.x through 10.11.12 allows a malicious remote server to bypass user ownership validation. No proof of concept, exploit code, or active exploitation claim is provided.

    0000032
    71 followersView on X
  • CVE@CVEnew
    Disclosure

    CVE-2026-27769 Mattermost versions 10.11.x &lt;= 10.11.12 fail to validate whether users were correctly owned by the correct Connected Workspace which allows a malicious remote server … https://www.cve.org/CVERecord?id=CVE-2026-27769

    Post summary

    The CVE describes a validation flaw in Mattermost that could let a malicious remote server impersonate workspace users. No PoC, exploit, or patch information is included.

    00000163
    57.2K followersView on X
  • Vulmon Vulnerability Feed@VulmonFeeds
    Disclosure

    CVE-2026-27769 Improper User Ownership Validation in Mattermost Connected Workspaces 10.11.x https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-27769

    Post summary

    The text announces CVE-2026-27769, an improper user ownership validation flaw in Mattermost Connected Workspaces 10.11.x, but does not provide any PoC, exploit, or mitigation details.

    0000038
    4.0K followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Appmattermostmattermost_server---

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