pecee simple-router up to 5.4.1.7 IpRestrictAccess X-Forwarded-For/CF-Connecting-IP/Client-IP incomplete blacklist

Summaryinfo

A vulnerability marked as critical has been reported in pecee simple-router up to 5.4.1.7. This impacts an unknown function of the component IpRestrictAccess. This manipulation of the argument X-Forwarded-For/CF-Connecting-IP/Client-IP causes incomplete blacklist. This vulnerability is registered as CVE-2026-103592. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability has been found in pecee simple-router up to 5.4.1.7 and classified as critical. Affected by this vulnerability is an unknown code of the component IpRestrictAccess. The manipulation of the argument X-Forwarded-For/CF-Connecting-IP/Client-IP with an unknown input leads to a incomplete blacklist vulnerability. The CWE definition for the vulnerability is CWE-184. The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete, leading to resultant weaknesses. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

simple-php-router through 5.4.1.7 contains an IP restriction bypass vulnerability in the IpRestrictAccess middleware that allows remote unauthenticated attackers to bypass IP whitelist and blacklist protections. Attackers can spoof X-Forwarded-For, CF-Connecting-IP, or Client-IP headers to impersonate whitelisted addresses or evade blacklists, gaining access to IP-restricted routes.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-103592 since 10/01/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/01/2026). MITRE ATT&CK project uses the attack technique T1562.006 for this issue.

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

Type

• Router Operating System

Vendor

• pecee

Name

• simple-router

Version

• 5.4.1.0
• 5.4.1.1
• 5.4.1.2
• 5.4.1.3
• 5.4.1.4
• 5.4.1.5
• 5.4.1.6
• 5.4.1.7

CPE 2.3info

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CPE 2.2info

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

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