Vulnerability in Linksys E5600

[ Why it matters ]Priority signals

• Urgent advisory from BSI

[ Description ]Official description

A security flaw has been discovered in Linksys E5600 1.1.0.26. Affected by this issue is the function init_multipart of the file /cgi-bin/upload_fw.cgi of the component Header Parser. The manipulation results in out-of-bounds write. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks. 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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund3 Nov 2026WID-SEC-2026-4327

  Linksys Router E5600: Multiple vulnerabilities allow privilege escalation Translated from German

  Risk criticalCVE-2026-121616CVE-2026-121615CVE-2026-121618+1 more CVEs

[ References ]References

• github.com/Zimo-666/E5600-cves/tree/main/04-upload-fw-multipart-overflow
• vuldb.com/cve/CVE-2026-121617
• vuldb.com/submit/1023313
• vuldb.com/vuln/430465
• vuldb.com/vuln/430465/cti
• www.linksys.com