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CVE-2026-79662— Ech0 before 4.7.3 OAuth Redirect URI Validation Bypass

Quick assessment

Affected
lin-snow Ech0
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Ech0 4.5.6 及之前版本在 （位于 ）中存在 OAuth 重定向 URI 验证漏洞。该函数仅比对学生提供的 的协议（scheme）和主机名（host）与管理员配置的允许列表（allowlist），而忽略了路径（path）、查询字符串（query）和片段标识符（fragment）部分。在登录过程中， 会被嵌入到签名状态 JWT 中，且未经过充分验证。 攻击者可构造一个主机名匹配允许来源、但路径由攻击者控制的 。在完成 OAuth 流程后，受害者将被重定向至该路径，且一次性交换代码（exchange code）

CVSS 8.0 · High

Affected Version Matrix 2

VendorProduct Version RangeStatus
lin-snow Ech0 < 4.7.3 affected
4.7.3 unaffected
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I. Basic Information for CVE-2026-79662

Vulnerability Information
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Vulnerability Title
Ech0 before 4.7.3 OAuth Redirect URI Validation Bypass
Source: CVE Program / CVE List V5
Vulnerability Description
Ech0 through 4.5.6 contains an OAuth redirect URI validation vulnerability in parseAndValidateClientRedirect (internal/service/auth/auth.go) that compares only the scheme and host of the client-supplied redirect_uri against the admin-configured allowlist, ignoring path, query, and fragment components. The redirect_uri is embedded into the signed state JWT at login time without validation. An attacker can craft a redirect_uri whose host matches an allowed origin but whose path is attacker-influenced; after the OAuth exchange the victim is redirected to that path with a one-time exchange code in the query string. If the code leaks (e.g., via Referer, analytics, or an open redirect on that host), the attacker can trade it at the public POST /api/auth/exchange endpoint for the victim's access and refresh tokens. Fixed in 4.7.3.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
指向未可信站点的URL重定向(开放重定向)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
lin-snow Ech0 0 ~ 4.7.3 -

II. Public POCs for CVE-2026-79662

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 11473 chars
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Trigger conditions & impact
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Exploit chain & mitigation
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III. Intelligence Information for CVE-2026-79662

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Vendor Advisories for CVE-2026-79662 (2)

Same Patch Batch · lin-snow · 2026-08-25 · 16 CVEs total

CVE-2026-79665 8.8 HIGH Ech0 before 4.5.1 Authorization Bypass via Session Tokens
CVE-2026-79659 7.7 HIGH Ech0 before 4.7.3 Server-Side Request Forgery via fetchPeerConnectInfo
CVE-2026-79667 7.6 HIGH Ech0 before 4.4.3 Authentication Bypass via Scope Enforcement
CVE-2026-79658 7.5 HIGH Ech0 before 5.0.1 Denial of Service via Accept-Language
CVE-2026-79664 7.4 HIGH Ech0 before 4.7.3 Access Token Revocation Bypass
CVE-2026-79673 6.5 MEDIUM Ech0 before 4.4.3 Scope Bypass via profile:read Token
CVE-2026-79661 6.5 MEDIUM Ech0 before 4.7.3 Unauthenticated fav_count Modification
CVE-2026-79666 6.5 MEDIUM Ech0 before 4.4.3 Missing Authorization via dashboard log endpoints
CVE-2026-79672 5.5 MEDIUM Ech0 before 4.4.3 Authentication Bypass via Comment Panel
CVE-2026-79671 5.5 MEDIUM Ech0 before 4.4.3 SSRF via DNS Resolution Bypass
CVE-2026-79660 5.3 MEDIUM Ech0 before 4.7.3 Email Disclosure via Public API
CVE-2026-79668 5.3 MEDIUM Ech0 before 4.7.3 Unauthenticated Like Endpoint Metric Inflation
CVE-2026-79670 4.8 MEDIUM Ech0 before 4.4.3 Stored XSS via SVG Upload
CVE-2026-79663 4.8 MEDIUM Ech0 before 4.7.3 Stored XSS via RSS feed tag names
CVE-2026-79669 4.3 MEDIUM Ech0 before 4.4.3 Missing Authorization on System Logs

IV. Related Vulnerabilities

Same product: Ech0
Same vendor: lin-snow
Same weakness: CWE-601

V. Comments for CVE-2026-79662

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