CVE-2026-5308
📛 CVE Title
Missing request body size limits on Zoom plugin HTTP endpoints
Description
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646
Overview
- State
- PUBLISHED
- Assigner (CNA)
- Mattermost
- CVSS severity
- MEDIUM
- CVSS score
- 4.9 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H- Effective score
- 4.9 / 10 MEDIUM source: CNA overview
- CWE(s)
-
CWE-400 - Reserved
- 2026-04-01
- Published
- 2026-05-22 10:20 UTC
- Last updated
- 2026-05-22 12:14 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/5xxx/CVE-2026-5308.json
- Linked Threat
- CVE-2026-5308 — CVE-2026-5308
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- EPSS score
- 0.0004 (probability of exploitation in next 30 days)
- EPSS percentile
- 11.05% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24
NVD / KEV / EPSS data refreshed 2026-05-25 00:20 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2026-31425 - Assigner
- Mattermost
- Published
- May 22, 2026, 10:20:43 AM
- Updated
- May 22, 2026, 12:14:58 PM
- EUVD base score (CVSS 3.1)
-
4.9 / 10
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - EUVD-reported EPSS
- 0.0500
- Vendors
- Mattermost
- Products
-
Mattermost (11.4.0 ≤11.4.4)Mattermost (10.11.0 ≤10.11.14)Mattermost (11.5.0 ≤11.5.3)Mattermost (11.6.0 ≤11.6.0)
- Aliases
-
GHSA-jmvr-r5hm-fxfr
ENISA description: Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646
EUVD references (1)
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Mattermost | Mattermost |
11.6.0 (affected),
11.5.0 (affected),
11.4.0 (affected),
10.11.0 (affected),
11.7.0 (unaffected),
11.6.1 (unaffected),
11.5.4 (unaffected),
11.4.5 (unaffected),
10.11.15 (unaffected)
|
— |
Vendor references (1)
References embedded in the original CVE record by the assigning CNA.
- MMSA-2026-00646 vendor-advisory
Web references (4)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- https://www.first.org/epss/ tenable:www.first.org
- https://mattermost.com/security-updates tenable:mattermost.com
- https://nvd.nist.gov/vuln/detail/CVE-2026-5308 tenable:nvd.nist.gov
- https://www.cve.org/CVERecord?id=CVE-2026-5308 tenable:www.cve.org
Remediations (19)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:blog.talosintelligence.com
Microsoft has released its monthly security update for May 2026 , which includes 137 vulnerabilities affecting a range of products, including 16 that Microsoft marked as "critical".
2026-05-26 03:10 UTC -
web:cyberpress.org
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .
2026-05-26 03:10 UTC -
web:cyberscoop.com
Threats Microsoft addresses 137 vulnerabilities in May's Patch Tuesday, including 13 rated critical The high volume of vulnerabilities reflects a growing trend researchers have been anticipating as artificial intelligence models are deployed to find previously uncovered defects in code.
2026-05-26 03:10 UTC -
web:cybersecuritynews.com
Microsoft released its March 2026 Patch Tuesday security update on March 10, 2026 , addressing 78 vulnerabilities across Windows, Microsoft Office, Azure, SQL Server, and .NET. The update includes one actively exploited zero-day vulnerability and multiple Critical-rated flaws demanding immediate attention from security teams. The most urgent fix this month is CVE - 2026 -21262, the sole zero-day ...
2026-05-26 03:10 UTC -
web:nvd.nist.gov
An official website of the United States government NVD MENU
2026-05-26 03:10 UTC -
web:thehackernews.com
Microsoft patched 138 flaws, including 30 Critical bugs, as AI discovery expands Patch Tuesday risk.
2026-05-26 03:10 UTC -
web:vulert.com
Microsoft's May 2026 Patch Tuesday fixes 138 vulnerabilities, including critical Windows DNS and Netlogon RCE flaws. Learn the risks, key CVEs , mitigation steps, and how Vulert can help.
2026-05-26 03:10 UTC -
web:www.linkedin.com
Microsoft has released its May 2026 Patch Tuesday security updates, addressing more than 130 vulnerabilities across its software ecosystem, including Windows, Microsoft Office, SharePoint Server ...
2026-05-26 03:10 UTC -
web:www.microsoft.com
Security Update Guide Notifications Microsoft's free Security Update Guide Notifications provide links to security-related software updates and notification of re-released security updates. These notifications are sent via email throughout the month as needed.
2026-05-26 03:10 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-05-26 03:10 UTC -
web:blog.qualys.com
Key Takeaways RedSun is a critical zero-day vulnerability in Microsoft Defender that allows low-privileged users to gain SYSTEM access No patch is currently available, leaving all Defender-enabled Windows systems potentially exposed Qualys VMDR detects affected assets instantly (QID 92382) TruRisk™ Eliminate enables immediate mitigation , removing exploitability without waiting for a fix ...
2026-06-03 22:33 UTC -
web:blog.qualys.com
May 2026's Patch Tuesday arrives with Microsoft addressing a fresh set of vulnerabilities across its ecosystem, reinforcing the ongoing need for timely patching in an increasingly threat-heavy…
2026-06-03 22:33 UTC -
web:cybersecuritynews.com
Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.
2026-06-03 22:33 UTC -
web:hivepro.com
Summary Microsoft's May 2026 Patch Tuesday security update addresses 137 critical vulnerabilities across the Microsoft product ecosystem, representing a significant security update for enterprise and consumer environments.
2026-06-03 22:33 UTC -
web:nvd.nist.gov
An official website of the United States government Here's how you know
2026-06-03 22:33 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-06-03 22:33 UTC -
web:support.microsoft.com
This out-of-band update for Windows 11, version 25H2 and 24H2 (KB5085518) includes fixes and improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates ...
2026-06-03 22:33 UTC -
web:thecyberexpress.com
Microsoft has rolled out its May 2026 Patch Tuesday security updates, delivering fixes for approximately 120 vulnerabilities across Windows, Microsoft Office, networking services, and enterprise platforms.
2026-06-03 22:33 UTC -
web:www.lansweeper.com
Which vulnerabilities, issues, and other things did Microsoft update? Discover what's new using Lansweeper's Patch Tuesday May 2026 summary.
2026-06-03 22:33 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-5308.json.
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