# CVE-2026-75628: Punk::OAuth2 versions before 0.03 for Perl allow an attacker-chosen off-site redirect after login because same_origin_path accepts a backsla

> Attackers can redirect users to malicious sites after login due to insufficient validation of the return parameter in Punk::OAuth2.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 20 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** GHSA-v6g5-xxrx-m495

## What is CVE-2026-75628?

CVE-2026-75628 is a medium-severity vulnerability, published on 20 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Punk::OAuth2 versions before 0.03 for Perl allow an attacker-chosen off-site redirect after login because same_origin_path accepts a backslash or tab in the return parameter.

oauth2_login reads the return parameter from the initiation request, runs same_origin_path over it, and stores the survivor in the session flow record as the post-login redirect target. That check rejects a value that does not begin with a slash, one with a slash as its second byte, and one containing CR or LF. A backslash and a tab pass. The URL Standard treats a backslash as equivalent to a slash for special schemes, so `/\evil.example` parses with the authority `evil.example`. It also strips ASCII tab before parsing, so a tab between two leading slashes leaves `//evil.example`.

A crafted link to the application's own login route lands the victim on the attacker's site after a genuine authentication. The redirect carries no authorization code or access token.

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

## Which versions are affected by CVE-2026-75628?


## How do I fix CVE-2026-75628?

No fix has been published for CVE-2026-75628 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-75628 being exploited?

There is no known exploitation of CVE-2026-75628 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75628 and fix it if it is affected.

What it is: CVE-2026-75628 is a medium-severity vulnerability, published on 20 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-75628 in the wild and no public exploit code.

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-2026-75628/ (Markdown: https://insights.sbomify.com/CVE-2026-75628/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75628
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75628
- OSV: https://osv.dev/vulnerability/CVE-2026-75628

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75628/
Summaries are generated and may contain mistakes; the official description above is the record.