# CVE-2026-82464: pac4j-core before 6.5.6 Open Redirect via Backslash Logout

> Attackers can redirect users to malicious sites after logout via crafted backslash-prefixed URLs in the pac4j security library.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 29 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** GHSA-f668-xfp8-vhf5

## What is CVE-2026-82464?

CVE-2026-82464 is a medium-severity vulnerability in pac4j, published on 29 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

pac4j-core before 6.5.6 contains an open redirect vulnerability in DefaultLogoutLogic.perform() that accepts backslash-prefixed logout redirect targets matching logoutUrlPattern. Attackers can craft logout links with backslash-prefixed external hosts that browsers normalize into network-path references, redirecting victims to attacker-controlled sites after logout.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2026-82464?


## How do I fix CVE-2026-82464?

No fix has been published for CVE-2026-82464 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-82464 being exploited?

There is no known exploitation of CVE-2026-82464 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82464 and fix it if it is affected.

What it is: CVE-2026-82464 is a medium-severity vulnerability in pac4j, published on 29 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-82464 in the wild and no public exploit code.

Affected product: pac4j. 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-2026-82464/ (Markdown: https://insights.sbomify.com/CVE-2026-82464/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82464
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82464
- OSV: https://osv.dev/vulnerability/CVE-2026-82464

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82464/
Summaries are generated and may contain mistakes; the official description above is the record.