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CVE-2026-73255— Mongoose: Path traversal in SSI #include directives enables arbitrary file read

Quick assessment

Affected
cesanta mongoose
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.

Mongoose 是一个嵌入式 Web 服务器和网络库。在版本 7.22 之前，如果攻击者能够控制启用了 SSI（服务器端包含）的文件，则可以在 #include 文件或 #include virtual 指令中插入目录遍历序列。src/ssi.c 中的 mg_ssi() 函数在将指令参数拼接到文件系统路径时，未调用 mg_path_is_sane() 进行安全检查，从而导致在配置了 ssi_pattern 且启用了 MG_ENABLE_SSI 的部署环境中，攻击者可以读取 Mongoose 进程有权访问的文件。该

CVSS 6.5 · Medium EPSS 0.59% · P46

Possible ATT&CK Techniques 1 AI

T1083 · File and Directory Discovery

Affected Version Matrix 1

VendorProduct Version RangeStatus
cesanta mongoose < 7.22 affected
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I. Basic Information for CVE-2026-73255

Vulnerability Information
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Vulnerability Title
Mongoose: Path traversal in SSI #include directives enables arbitrary file read
Source: CVE Program / CVE List V5
Vulnerability Description
Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can control an SSI-enabled file can place directory traversal sequences in an #include file or #include virtual directive. The mg_ssi() function in src/ssi.c concatenates the directive argument into a filesystem path without calling mg_path_is_sane(), allowing an MG_ENABLE_SSI deployment with ssi_pattern configured to disclose files readable by the Mongoose process. This issue is fixed in version 7.22.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
cesanta mongoose < 7.22 -

II. Public POCs for CVE-2026-73255

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III. Intelligence Information for CVE-2026-73255

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Patches & Fixes for CVE-2026-73255 (1)

Vendor Advisories for CVE-2026-73255 (1)

Vendor Pages for CVE-2026-73255 (1)

Same Patch Batch · cesanta · 2026-08-20 · 8 CVEs total

CVE-2026-73251 9.3 CRITICAL Mongoose Built-in TLS: CA-bundle certificate chain accepted without any signature verifica
CVE-2026-73257 9.1 CRITICAL Mongoose: Content-Length + Transfer-Encoding coexistence enables request smuggling
CVE-2026-73256 9.1 CRITICAL Mongoose: HTTP/1.0 detection off-by-one enables request smuggling via chunked TE
CVE-2026-73253 9.1 CRITICAL Mongoose: TLS Hostname Verification Bypass via Overly Permissive Wildcard Matching
CVE-2026-73258 6.5 MEDIUM Mongoose: Multipart boundary/header scan logic error in mg_http_next_multipart
CVE-2026-73254 5.4 MEDIUM Mongoose: Stored XSS via unescaped filenames in directory listing
CVE-2026-73259 5.4 MEDIUM Mongoose: Reflected XSS via decoded URI in directory listing render

IV. Related Vulnerabilities

Same product: mongoose
Same vendor: cesanta
Same weakness: CWE-22

V. Comments for CVE-2026-73255

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