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TI-2026-84922 Aliases CVE-2026-121617GHSA-ch52-qqqr-2wgh

Out-of-bounds write in Linksys E5600 firmware upload parser

Priority LOW 38CWE-119Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-119 and the CVSS impact.

Summary

Linksys E5600 from 1.1.0.26 contains an out-of-bounds write in the init_multipart function of /cgi-bin/upload_fw.cgi (CWE-787). The Header Parser component writes past the end of a buffer. A remote attacker can trigger it without authentication, and a public exploit has been released. The vendor did not respond to early disclosure, and the maintainer no longer supports the product.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

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.

Why it matters now

EPSS 0.0047 40th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinksysE56001.1.0.26—No fix listedCNA
  • E5600 VendorLinksys Affected 1.1.0.26 Fixed in — No fix listed CNA

CPE names CNA · 1

CPEVersionsRoleVendor
cpe:2.3:o:linksys:e5600_firmware:*:*:*:*:*:*:*:*——Linksys
  • cpe:2.3:o:linksys:e5600_firmware:*:*:*:*:*:*:*:* Versions — — ·Linksys

Remediation

The sources list no fixed version for Linksys E5600.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-121617
  2. 2026-11-04 Alias added: GHSA-ch52-qqqr-2wgh
  3. 2026-11-05 Priority changed: MEDIUM → LOW

References

Exploit 1

Other 1

  • TI-2025-24206 Linksys Routers E/WAG/WAP/WES/WET/WRT-Series CVSS 4.0CRITICAL 10.0
  • TI-2017-12715 OS command injection in Linksys WVBR0 CVSS 3.0CRITICAL 9.8
  • TI-2026-70977 Stack-based buffer overflow in Linksys E1700 Mac Filter CVSS 4.0CRITICAL 10.0
  • TI-2026-22199 Missing neutralization in Linksys MR9600, Linksys MX4200 CVSS 3.1CRITICAL 9.8
  • TI-2026-22198 Missing neutralization in Linksys MR9600, Linksys MX4200 CVSS 3.1CRITICAL 9.8
  • TI-2026-22197 Missing authentication in Linksys MR9600, Linksys MX4200 CVSS 3.1CRITICAL 9.8
See all 253 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences