--- title: "Mattermost fails to properly validate User-Agent header tokens" system_id: "mattermost" category: "platforms" advisory_mode: "core" published_date: "2026-03-16T15:30:42Z" updated_date: "2026-03-26T21:11:24.090883Z" severity: "low" exploit_status: "unknown" source_confidence: "ecosystem-authority" verification_status: "triage-manual" verification_mode: "synthetic" artifact_mode: "synthetic" last_run_id: "" target_types: - "lab-local" - "lab-public" - "authorized-third-party" allow_public_validation: "yes, with ownership or explicit authorization" authorization_prerequisite: "asset ownership proof or explicit written authorization" minimal_validation: "read-only probe, controlled payload, reversible test" aliases: - "CVE-2026-25783" - "GO-2026-4725" - "GHSA-2v3w-6g35-5f9v" affected_versions: - "introduced=0, fixed<8.0.0-20260129181235-1346cf529aef" - "introduced=0, fixed<5.3.2-0.20260129181235-1346cf529aef" - "introduced=10.11.0-rc1, fixed<10.11.11" - "introduced=11.2.0-rc1, fixed<11.2.3" - "introduced=11.3.0-rc1, fixed<11.3.1" - "introduced=10.11.0-rc1+incompatible, fixed<10.11.11+incompatible" - "introduced=0" fixed_versions: - "8.0.0-20260129181235-1346cf529aef" - "5.3.2-0.20260129181235-1346cf529aef" - "10.11.11" - "11.2.3" - "11.3.1" - "10.11.11+incompatible" - "11.2.3+incompatible" - "11.3.1+incompatible" entity_refs: - "mattermost:system:root-system" - "mattermost--repo--github-com-mattermost-mattermost-server:repo:affected-component" secure_code_topics: - "authz-server-side-recheck" - "xss-output-encoding" - "token-cookie-storage" - "dependency-upgrade-policy" primary_source: "https://nvd.nist.gov/vuln/detail/CVE-2026-25783" --- # Mattermost fails to properly validate User-Agent header tokens ## 本地实证状态 - 实证状态: `triage-manual` - 实证方式: `synthetic` - Artifact 模式: `synthetic` - 最近运行: `-` - 浏览器证据: `missing` - Run Bundle: `-` ## 事件层 - Canonical ID: `mattermost--CVE-2026-25783` - 系统: `mattermost` - 严重度: `low` - 来源置信度: `ecosystem-authority` - 官方主源: https://nvd.nist.gov/vuln/detail/CVE-2026-25783 - 影响版本: `introduced=0, fixed<8.0.0-20260129181235-1346cf529aef, introduced=0, fixed<5.3.2-0.20260129181235-1346cf529aef, introduced=10.11.0-rc1, fixed<10.11.11, introduced=11.2.0-rc1, fixed<11.2.3, introduced=11.3.0-rc1, fixed<11.3.1, introduced=10.11.0-rc1+incompatible, fixed<10.11.11+incompatible, introduced=0` - 修复版本: `8.0.0-20260129181235-1346cf529aef, 5.3.2-0.20260129181235-1346cf529aef, 10.11.11, 11.2.3, 11.3.1, 10.11.11+incompatible, 11.2.3+incompatible, 11.3.1+incompatible` ## 对象与版本映射 - Advisory Scope: `repo` - 影响对象: `mattermost / mattermost-server` - Entity Refs: `mattermost, mattermost--repo--github-com-mattermost-mattermost-server` - 版本置信度: `high` - 版本缺口: `-` - 版本证据源: `https://nvd.nist.gov/vuln/detail/CVE-2026-25783, https://github.com/advisories/GHSA-2v3w-6g35-5f9v, https://github.com/mattermost/mattermost/commit/1346cf529aef0672c39a56ec10d1b8a9c8fb387d, https://github.com/mattermost/mattermost, https://mattermost.com/security-updates` ## 受控验证流程 - Workflow ID: `mattermost--CVE-2026-25783--workflow` - 漏洞家族: `session-token` - 入口面: `session-or-token-processing` - 需要角色: `authenticated-user` - 触发向量: 对 `session-token` 家族入口投递最小化、可审计、可回滚的受控输入，比较修复前后差异。 - 请求/页面入口: `/login, /callback, /session` - 输入形态: 使用短期测试令牌或会话，验证生命周期、绑定与失效逻辑。 - 预期不安全行为: 令牌或会话可被重放、固定或越权使用。 ## 其他来源 - https://github.com/advisories/GHSA-2v3w-6g35-5f9v - https://github.com/mattermost/mattermost/commit/1346cf529aef0672c39a56ec10d1b8a9c8fb387d - https://github.com/mattermost/mattermost - https://mattermost.com/security-updates ## 证据点与补丁验证 ### 服务端证据点 - 应用日志中的命中路径、鉴权决策和异常栈 - 反向代理或边界层日志中的请求头、来源 IP 与路由决策 ### 浏览器证据点 - 基线截图与攻击后截图的 DOM/视觉差异 - console、network 与 response metadata 中的异常信号 ### 数据库/文件系统证据点 - 数据库中新增/越权读取的测试数据 - 文件系统中新增上传样本、缓存条目或越权读取痕迹 ### 检测信号 - WAF / reverse proxy 异常日志、访问日志和告警 - 应用审计日志中的权限错误、重定向异常、模板渲染或上传落盘事件 ### 补丁验证步骤 - 确认目标版本从 `introduced=0, fixed<8.0.0-20260129181235-1346cf529aef, introduced=0, fixed<5.3.2-0.20260129181235-1346cf529aef, introduced=10.11.0-rc1, fixed<10.11.11` 升级或回移到 `8.0.0-20260129181235-1346cf529aef`。 - 保留同一组受控输入，在修复前后分别执行并比对响应、日志与浏览器证据。 - 确认修复后仅保留预期业务行为，不再触发越权、回显、异常渲染或错误请求。 - 补充 `session-token` 族自动化回归，避免同类路径在插件、主题或代理链中回归。 ### 实验安全备注 - 只使用回环地址、哨兵目标、无害样本或可回滚测试数据。 - 禁止造成持久破坏、越权下载真实数据或不可回滚 side effect。 - 如需浏览器证据，保留 baseline / proof 两份快照以及 console / network 记录。 ## 实验层 - 仅用于自有资产、测试环境或已明确授权目标。 - 允许公网可达目标，但必须满足资产归属或明确授权前提。 - 最小化验证方式: 最小化验证、只读探测、可审计回显、受控注入。 - 若该案例涉及插件、模块或扩展，应同时检查供应链与升级策略。 - 禁止场景: 无归属证明或无明确授权的公网目标；知名公共网站或与测试无关的第三方资产；会造成持久破坏、数据越权下载或不可回滚影响的动作 ## 修复示例 - [javascript-typescript:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/javascript-typescript/authz-server-side-recheck.md) - [nodejs:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/nodejs/authz-server-side-recheck.md) - [java:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/java/authz-server-side-recheck.md) - [php:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/php/authz-server-side-recheck.md) - [python:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/python/authz-server-side-recheck.md) - [ruby:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/ruby/authz-server-side-recheck.md) - [csharp:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/csharp/authz-server-side-recheck.md) - [go:authz-server-side-recheck](/Users/x/websafe/05-defense/secure-code/go/authz-server-side-recheck.md) - [javascript-typescript:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/javascript-typescript/xss-output-encoding.md) - [nodejs:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/nodejs/xss-output-encoding.md) - [java:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/java/xss-output-encoding.md) - [php:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/php/xss-output-encoding.md) - [python:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/python/xss-output-encoding.md) - [ruby:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/ruby/xss-output-encoding.md) - [csharp:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/csharp/xss-output-encoding.md) - [go:xss-output-encoding](/Users/x/websafe/05-defense/secure-code/go/xss-output-encoding.md) - [javascript-typescript:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/javascript-typescript/token-cookie-storage.md) - [nodejs:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/nodejs/token-cookie-storage.md) - [java:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/java/token-cookie-storage.md) - [php:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/php/token-cookie-storage.md) - [python:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/python/token-cookie-storage.md) - [ruby:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/ruby/token-cookie-storage.md) - [csharp:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/csharp/token-cookie-storage.md) - [go:token-cookie-storage](/Users/x/websafe/05-defense/secure-code/go/token-cookie-storage.md) - [javascript-typescript:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/javascript-typescript/dependency-upgrade-policy.md) - [nodejs:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/nodejs/dependency-upgrade-policy.md) - [java:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/java/dependency-upgrade-policy.md) - [php:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/php/dependency-upgrade-policy.md) - [python:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/python/dependency-upgrade-policy.md) - [ruby:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/ruby/dependency-upgrade-policy.md) - [csharp:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/csharp/dependency-upgrade-policy.md) - [go:dependency-upgrade-policy](/Users/x/websafe/05-defense/secure-code/go/dependency-upgrade-policy.md)