CVE-2026-2456— Denial of Service via Unbounded Memory Allocation in Integration Actions
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I. Basic Information for CVE-2026-2456
Vulnerability Information
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Vulnerability Title
Denial of Service via Unbounded Memory Allocation in Integration Actions
Source: NVD (National Vulnerability Database)
Vulnerability Description
Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
未经控制的内存分配
Source: NVD (National Vulnerability Database)
Vulnerability Title
Mattermost 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Mattermost是美国Mattermost公司的一个开源协作平台。 Mattermost 11.3.0及之前的11.3.x版本、11.2.2及之前的11.2.x版本和10.11.10及之前的10.11.x版本存在安全漏洞，该漏洞源于未能限制集成操作端点的响应大小，可能导致经过身份验证的攻击者通过恶意集成服务器返回任意大响应，造成服务器内存耗尽和拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Mattermost | Mattermost | 11.3.0 ~ 11.3.0 | - |
II. Public POCs for CVE-2026-2456
| # | POC Description | Source Link | Shenlong Link |
|---|
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Same Patch Batch · Mattermost · 2026-03-16 · 21 CVEs total
| CVE-2026-2476 | 7.6 HIGH | MS Teams plugin sensitive config values not properly masked in support packets |
| CVE-2026-24458 | 7.5 HIGH | DoS attack via login attempts with multi-megabyte passwords |
| CVE-2026-2462 | 6.6 MEDIUM | Admin RCE via Malicious Plugin Upload on CI Test Instances |
| CVE-2026-2454 | 5.8 MEDIUM | DoS in Calls plugin via malformed msgpack in websocket request. |
| CVE-2026-25783 | 4.3 MEDIUM | Denial of service via malformed User-Agent header in getBrowserVersion |
| CVE-2026-2463 | 4.3 MEDIUM | Unauthorized access to invite ID during team creation |
| CVE-2026-2461 | 4.3 MEDIUM | Missing authorization check allows unauthorized modification of other users' comments on a |
| CVE-2026-2457 | 4.3 MEDIUM | WebSocket Message Spoofing via Permalink Embed Manipulation |
| CVE-2026-2458 | 4.3 MEDIUM | Unauthorized channel enumeration in private teams after member removal |
| CVE-2026-26246 | 4.3 MEDIUM | Memory Exhaustion via Malformed PSD File Upload |
| CVE-2026-2578 | 4.3 MEDIUM | Information Disclosure via WebSocket Event When Deleting Unrevealed Burn on Read Posts |
| CVE-2026-1629 | 4.3 MEDIUM | Permalink Preview Information Disclosure After Permission Revocation |
| CVE-2026-4265 | 4.3 MEDIUM | Guest user can upload files without permission across teams |
| CVE-2026-25780 | 4.3 MEDIUM | Memory Exhaustion via Malformed DOC File Upload |
| CVE-2026-21386 | 4.3 MEDIUM | Private channel enumeration via /mute slash command |
| CVE-2026-2455 | 4.3 MEDIUM | SSRF bypass via IPv4-mapped IPv6 literals |
| CVE-2026-24692 | 4.3 MEDIUM | Guest users can bypass read permissions via search API |
| CVE-2026-26304 | 4.3 MEDIUM | Permission Bypass in Playbook Run Creation |
| CVE-2026-26230 | 3.8 LOW | Team Admin Privilege Escalation to Demote Members to Guest |
| CVE-2026-22545 | 3.1 LOW | Password Change Bypass via Auth Switch Endpoint |
IV. Related Vulnerabilities
Same product: Mattermost
- CVE-2026-3590
Race Condition in Guest Magic Link Authentication Allows Tok - CVE-2026-28741
CSRF Protection Bypass Allows Updating a User's Authenticati - CVE-2026-27769
Connected Workspaces: Malicious remote server can manipulate - CVE-2026-24661
Unbounded Request Body Read in MS Teams Plugin {{/changes}} - CVE-2026-21388
Unbounded Request Body Read in MS Teams Plugin {{/lifecycle}
Same vendor: Mattermost
- CVE-2026-3590
Race Condition in Guest Magic Link Authentication Allows Tok - CVE-2026-28741
CSRF Protection Bypass Allows Updating a User's Authenticati - CVE-2026-27769
Connected Workspaces: Malicious remote server can manipulate - CVE-2026-24661
Unbounded Request Body Read in MS Teams Plugin {{/changes}} - CVE-2026-21388
Unbounded Request Body Read in MS Teams Plugin {{/lifecycle}
Same weakness: CWE-789
- CVE-2021-47944
memono Notepad 4.2 Denial of Service via Buffer Overflow - CVE-2026-42241
ParquetSharp: Possible Stack Overflow When Reading a Parquet - CVE-2026-43868
Apache Thrift: Rust implementation vulnerable to CVE-2020-13 - CVE-2026-42146
CImg Library: Uncontrolled memory allocation via nb_colors f - CVE-2026-42440
Apache OpenNLP: OOM DoS via Unbounded Array Allocation in Ab
V. Comments for CVE-2026-2456
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