# CVE-2026-18660: Jetty proxy blacklist performs case-sensitive matching of case-insensitive DNS hostnames

> Attackers can bypass Jetty proxy host blacklists by using case variations in hostnames, potentially enabling Server-Side Request Forgery attacks.

- **Severity:** High 8.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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:** Yes
- **Published:** 15 Oct 2026
- **Updated:** 15 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-18660, GHSA-7wfj-j486-mxrf, UBUNTU-CVE-2026-18660

## What is CVE-2026-18660?

CVE-2026-18660 is a high-severity server-side request forgery vulnerability, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse Jetty, across various versions of `jetty-server`, and `jetty-proxy`, the host whitelist/blacklist is case-sensitive, and would allow hosts through that only differ by case.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-178 (Improper Handling of Case Sensitivity)

## Which versions are affected by CVE-2026-18660?


## How do I fix CVE-2026-18660?

Apply the vendor's patch.

## Is CVE-2026-18660 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18660 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-18660 and fix it if it is affected.

What it is: CVE-2026-18660 is a high-severity server-side request forgery vulnerability, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18660 exists.

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-2026-18660/ (Markdown: https://insights.sbomify.com/CVE-2026-18660/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-18660
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18660
- OSV: https://osv.dev/vulnerability/CVE-2026-18660

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-18660/
Summaries are generated and may contain mistakes; the official description above is the record.