Linksys E5600 1.1.0.26 Header Parser /cgi-bin/upload_fw.cgi init_multipart out-of-bounds write

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.1$0-$5k2.59

Summaryinfo

A vulnerability was found in Linksys E5600 1.1.0.26. It has been rated as critical. This affects the function init_multipart of the file /cgi-bin/upload_fw.cgi of the component Header Parser. This manipulation causes out-of-bounds write. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability is registered as CVE-2026-121617. Remote exploitation of the attack is possible. Furthermore, an exploit is available. The vendor was contacted early about this disclosure but did not respond in any way.

Detailsinfo

A vulnerability has been found in Linksys E5600 1.1.0.26 and classified as critical. Affected by this vulnerability is the function init_multipart of the file /cgi-bin/upload_fw.cgi of the component Header Parser. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect availability.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-121617. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details and also a public exploit are known.

It is possible to download the exploit at github.com. It is declared as proof-of-concept. The vendor was contacted early about this disclosure but did not respond in any way.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.5
VulDB Temp Score: 7.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/03/2026 Advisory disclosed
11/03/2026 +0 days VulDB entry created
11/03/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: linksys.com

Advisory: github.com
Status: Confirmed

CNA: VulDB
CVE: CVE-2026-121617 (🔒)

GCVE (CVE): GCVE-0-2026-121617
GCVE (VulDB): GCVE-100-430465
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 11/03/2026 17:45
Changes: 11/03/2026 17:45 (59)
Complete: 🔍
Submitter: liuyingqi
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #1023313: Linksys E5600 1.1.0.26 Buffer Overflow - Out-of-bounds Write (CWE-787) (by liuyingqi)

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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