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CVE-2026-79658— Ech0 before 5.0.1 Denial of Service via Accept-Language

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.

L1nSn0w Ech0是L1nSn0w个人开发者的一款功能综合的实用工具。 L1nSn0w Ech0 5.0.1之前版本存在资源管理错误漏洞，该漏洞源于未对Accept-Language头施加大小或形状限制，可能导致二次时间复杂度的解析，造成CPU消耗，从而引发拒绝服务。

CVSS 7.5 · High EPSS 0.51% · P42

Affected Version Matrix 2

VendorProduct Version RangeStatus
lin-snow Ech0 < 5.0.1 affected
5.0.1 unaffected
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I. Basic Information for CVE-2026-79658

Vulnerability Information
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Vulnerability Title
Ech0 before 5.0.1 Denial of Service via Accept-Language
Source: CVE Program / CVE List V5
Vulnerability Description
Ech0 before 5.0.1 does not impose any size or shape limit on the Accept-Language header processed by its i18n middleware, which runs on every HTTP request. The header is passed unfiltered to go-i18n's NewLocalizer, which internally calls golang.org/x/text/language.ParseAcceptLanguage. The CVE-2022-32149 mitigation in x/text caps '-' characters but not '_' characters, which the parser aliases to '-', allowing quadratic-time parsing to be triggered with a large header (up to Go's default 1 MiB) built from underscore separators. An unauthenticated attacker can send such requests to consume roughly 1.5 seconds of CPU each, and concurrent requests can saturate a multi-core server (denial of service).
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
L1nSn0w Ech0 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
L1nSn0w Ech0是L1nSn0w个人开发者的一款功能综合的实用工具。 L1nSn0w Ech0 5.0.1之前版本存在资源管理错误漏洞，该漏洞源于未对Accept-Language头施加大小或形状限制，可能导致二次时间复杂度的解析，造成CPU消耗，从而引发拒绝服务。
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
lin-snow Ech0 0 ~ 5.0.1 -

II. Public POCs for CVE-2026-79658

# POC Description Source Link Shenlong Link
AI-Generated POC Verified env Premium
Reproduced successfully in a real sandbox · Below is the actual recording of building the environment and exploiting the vulnerability.
Success marker: VULNERABLE: ReDoS measured net delta 423 ms (threshold 250 ms) from 1MiB underscore-heavy Accept-Language
Reproduction recording is a Pro+ exclusive
Watch the full sandbox build + live exploit recording for this CVE. Limited-time ¥499/mo.
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claude_code · 9170 chars
GitHub 复现环境（可 clone 直接跑）
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
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POC zip download
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III. Intelligence Information for CVE-2026-79658

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Vendor Advisories for CVE-2026-79658 (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-2026-79662 8.0 HIGH Ech0 before 4.7.3 OAuth Redirect URI Validation Bypass
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-2026-79664 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-400

V. Comments for CVE-2026-79658

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