CVE-2026-121615— Linksys E5600 Login mesh_login.cgi improper authentication

Quick assessment

Affected

Linksys E5600

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.

Linksys E5600 固件版本 1.1.0.26 存在一处漏洞。该漏洞影响登录处理组件中文件内的某个未知功能。通过执行恶意操作，可能导致身份验证机制失效。该攻击可远程发起，且利用代码已在公开渠道披露，可能被恶意利用。厂商已在此漏洞披露初期被通知，但至今未作任何回应。此漏洞仅影响不再由维护方提供支持的产品。

CVSS 10.0 · Critical Updated Nov 04, 2026

Possible ATT&CK Techniques 2 AI

T1078 · Valid Accounts T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

Linksys E5600 Login mesh_login.cgi improper authentication

Source: CVE Program / CVE List V5

Vulnerability Description

A vulnerability was determined in Linksys E5600 1.1.0.26. Affected is an unknown function of the file /cgi-bin/mesh_login.cgi of the component Login Handler. Executing a manipulation can lead to improper authentication. The attack can be launched remotely. The exploit has been publicly disclosed and may be utilized. The vendor was contacted early about this disclosure but did not respond in any way. This vulnerability only affects products that are no longer supported by the maintainer.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

认证机制不恰当

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
Linksys	E5600	1.1.0.26	`cpe:2.3:o:linksys:e5600_firmware::::::::`

II. Public POCs for CVE-2026-121615

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III. Intelligence Information for CVE-2026-121615

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Other References for CVE-2026-121615 (5)

https://github.com/Zimo-666/E5600-cves/tree/main/02-mesh-login-auth-bypass exploit
https://vuldb.com/cve/CVE-2026-121615 third-party-advisory
https://vuldb.com/vuln/430463/cti signature permissions-required
https://vuldb.com/vuln/430463 vdb-entry
https://vuldb.com/submit/1023310 third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-121615

Same Patch Batch · Linksys · 2026-11-04 · 4 CVEs total

CVE-2026-121617	7.5 HIGH	Linksys E5600 Header upload_fw.cgi init_multipart out-of-bounds write
CVE-2026-121616	5.3 MEDIUM	Linksys E5600 JSON Request mesh_login.cgi strcpy out-of-bounds write
CVE-2026-121618	5.3 MEDIUM	Linksys E5600 Factory Quality Control fqc.cgi information disclosure

IV. Related Vulnerabilities

Same product: E5600

Same vendor: Linksys

Same weakness: CWE-287