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

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linksys / E5600: 1.1.0.26 (affected). Source: CNA: VulDB

## Severity and prioritization

- CVSS 4.0: 10 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P; source: CNA: VulDB

- CVSS 3.1: 10 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 3.0: 10 (critical); CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 2.0: 10 (critical); AV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:C; source: CNA: VulDB

- CVSS 4.0: 9.3 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: cna@vuldb.com

- CVSS 3.1: 10 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H; source: NVD: cna@vuldb.com

- CVSS 2.0: 10 (high); AV:N/AC:L/Au:N/C:C/I:C/A:C; source: NVD: cna@vuldb.com

- CISA KEV: No listing in collected sources

- EPSS: 0.75% as of 2026-11-04; percentile 55.22%

- SSVC: Not available

- Weaknesses: CWE-287

## Exploit evidence

- exploit: https://github.com/Zimo-666/E5600-cves/tree/main/02-mesh-login-auth-bypass (CNA: VulDB)

## References

- https://vuldb.com/vuln/430463 (CNA: VulDB; vdb-entry)

- https://vuldb.com/vuln/430463/cti (CNA: VulDB; signature, permissions-required)

- https://vuldb.com/cve/CVE-2026-121615 (CNA: VulDB; third-party-advisory)

- https://vuldb.com/submit/1023310 (CNA: VulDB; third-party-advisory)

- https://github.com/Zimo-666/E5600-cves/tree/main/02-mesh-login-auth-bypass (CNA: VulDB; exploit)

- https://www.linksys.com/ (CNA: VulDB; product)

- https://github.com/Zimo-666/E5600-cves/tree/main/02-mesh-login-auth-bypass (cna@vuldb.com)

- https://vuldb.com/cve/CVE-2026-121615 (cna@vuldb.com)

- https://vuldb.com/submit/1023310 (cna@vuldb.com)

- https://vuldb.com/vuln/430463 (cna@vuldb.com)

- https://vuldb.com/vuln/430463/cti (cna@vuldb.com)

- https://www.linksys.com/ (cna@vuldb.com)

## Provenance

- CNA: VulDB: https://www.cve.org/CVERecord?id=CVE-2026-121615; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121615; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-121615; retrieved 2026-11-05; source updated Not reported

Revision: 67fd376c219e272e108dfb1492736b33d17e3a9ed8d69ad0ebb91955333e4b38

Canonical: https://y2.dev/cve/CVE-2026-121615

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