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

> Attackers can bypass IP restrictions in simple-php-router by spoofing forwarding headers, gaining unauthorized access to protected routes.

- **Severity:** Medium 6.9 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 30 Sep 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-73j7-rxg8-5ccm

## What is CVE-2026-103592?

CVE-2026-103592 is a medium-severity authentication bypass vulnerability in pecee simple-router, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-348 (Use of Less Trusted Source)

## Which versions are affected by CVE-2026-103592?


## How do I fix CVE-2026-103592?

No fix has been published for CVE-2026-103592 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-103592 being exploited?

There is no known exploitation of CVE-2026-103592 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-103592 and fix it if it is affected.

What it is: CVE-2026-103592 is a medium-severity authentication bypass vulnerability in pecee simple-router, published on 30 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-103592 in the wild and no public exploit code.

Affected product: pecee simple-router. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-103592/ (Markdown: https://insights.sbomify.com/CVE-2026-103592/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-103592
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103592
- OSV: https://osv.dev/vulnerability/CVE-2026-103592

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-103592/
Summaries are generated and may contain mistakes; the official description above is the record.