# CVE-2026-66391: Apache Wicket: leaked and missing CSP headers

> Apache Wicket fails to properly generate or include Content Security Policy headers, allowing attackers to bypass CSP protections.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-r3h3-mj63-mm3p

## What is CVE-2026-66391?

CVE-2026-66391 is a medium-severity vulnerability in Apache Wicket, published on 27 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Use of Insufficiently Random Values, Protection Mechanism Failure vulnerability in Apache Wicket.

This issue affects Apache Wicket: from 9.0.0 through 9.23.0, from 10.0.0 through 10.9.0.

Users are recommended to upgrade to version 10.10.0, which fixes the issue.

Weakness: CWE-693 (Protection Mechanism Failure), CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2026-66391?

It affects 1 product.


Products: Apache Wicket.

## How do I fix CVE-2026-66391?

No fix has been published for CVE-2026-66391 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-66391 being exploited?

There is no known exploitation of CVE-2026-66391 in the wild and no public exploit code.

## Other vulnerabilities in Apache Wicket

- [CVE-2024-36522](https://insights.sbomify.com/CVE-2024-36522/): Apache Wicket: Remote code execution via XSLT injection (critical 9.8)
- [CVE-2026-40010](https://insights.sbomify.com/CVE-2026-40010/): Apache Wicket: possible session fixation using AuthenticatedWebSession (critical 9.1)
- [CVE-2016-6793](https://insights.sbomify.com/CVE-2016-6793/): Deserialization in n/a (critical 9.1)
- [CVE-2016-6806](https://insights.sbomify.com/CVE-2016-6806/): Apache Wicket vulnerable to CSRF attacks (high 8.8)
- [CVE-2026-71257](https://insights.sbomify.com/CVE-2026-71257/): Apache Wicket: Configured file upload limits are not enforced when the multipart request has already been parsed (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-66391 and fix it if it is affected.

What it is: CVE-2026-66391 is a medium-severity vulnerability in Apache Wicket, published on 27 Jul 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-2026-66391 in the wild and no public exploit code.

Affected product: Apache Wicket. 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-2026-66391/ (Markdown: https://insights.sbomify.com/CVE-2026-66391/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66391
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66391
- OSV: https://osv.dev/vulnerability/CVE-2026-66391

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-66391/
Summaries are generated and may contain mistakes; the official description above is the record.