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CVE-2026-118655— Echo: Static Middleware Double-Unescape Path Traversal

Quick assessment

Affected
labstack echo
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Echo 是一个基于 Go 的 Web 框架。在 4.15.3 和 5.2.0 版本之前， 会对 进行第二次解码，而该路径此前可能已经被解码过一次。因此，双重编码的路径分隔符会在文件系统解析之前被还原。如果静态中间件被全局注册，攻击者便可能借此访问受保护路由下的文件。该问题已在 4.15.3 和 5.2.0 版本中修复。

CVSS 5.9 · Medium

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-118655

Vulnerability Information
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Vulnerability Title
Echo: Static Middleware Double-Unescape Path Traversal
Source: CVE Program / CVE List V5
Vulnerability Description
Echo is a Go web framework. Prior to 4.15.3 and 5.2.0, middleware.Static can decode an already decoded Request.URL.Path a second time. Double-encoded separators can consequently be reconstructed before filesystem resolution. This can reach a file under a guarded route when the static middleware is registered globally. This issue is fixed in 4.15.3 and 5.2.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对同一数据的双重编码
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
labstack echo >= 5.0.0, < 5.2.0 -

II. Public POCs for CVE-2026-118655

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III. Intelligence Information for CVE-2026-118655

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Other References for CVE-2026-118655 (7)

Same Patch Batch · labstack · 2026-10-28 · 16 CVEs total

CVE-2026-118264 9.1 CRITICAL Echo: Rejected WebSocket upgrades can bypass Echo route-level access controls
CVE-2026-118260 8.2 HIGH Echo: BodyDump captures request and response bodies without size limits in v4
CVE-2026-118262 8.2 HIGH Echo: WebSocket proxy can retain connections and handlers after client disconnect
CVE-2026-118261 8.2 HIGH Echo: Decompress permits unbounded gzip expansion in v4
CVE-2026-118650 7.5 HIGH Echo: middleware.Static: `%2F`-encoded path bypasses route/group middleware guarding a sta
CVE-2026-118263 6.3 MEDIUM Echo: BodyDump can discard BodyLimit overflow errors for unknown-length requests
CVE-2026-118652 6.1 MEDIUM Echo: Reflected Cross-Site Scripting (XSS) via unsanitized JSONP callback in Context.JSONP
CVE-2026-118656 6.1 MEDIUM Echo: Open Redirect via Control-Character Prefix Defeating sanitizeURI
CVE-2026-118654 5.9 MEDIUM Echo static file middleware route protection bypass via encoded dot-dot traversal
CVE-2026-118657 5.9 MEDIUM Echo: HTTPS Redirect and HSTS Bypass via Unconditional Trust of Forwarded Scheme Headers
CVE-2026-118651 5.3 MEDIUM Echo: Reverse Proxy Forwards Attacker-Supplied X-Real-IP to Upstream by Default
CVE-2026-118266 5.3 MEDIUM Echo: CSRF Protection Bypass via MethodOverride Rewriting POST to Safe Method
CVE-2026-118265 5.3 MEDIUM Echo: X-Real-IP extractor trusts the header value instead of the sending peer
CVE-2026-118653 5.3 MEDIUM Echo: Rate Limiter Bypass via Spoofed X-Forwarded-For Header in Default Configuration
CVE-2026-118658 4.7 MEDIUM Echo: Arbitrary Scheme Injection in WWWRedirect/NonWWWRedirect Middlewares via X-Forwarded

IV. Related Vulnerabilities

Same product: echo
Same vendor: labstack
Same weakness: CWE-174