# CVE-2026-12811: kortix-ai suna Auth Endpoint page.tsx router.push cross site scripting

> Attackers can execute arbitrary scripts via the returnURL parameter in the auth endpoint, potentially leading to session hijacking or code execution.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P`)
- **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:** 21 Jun 2026
- **Updated:** 23 Jun 2026
- **Also known as:** GHSA-fpgm-v536-ccc8

## What is CVE-2026-12811?

CVE-2026-12811 is a medium-severity cross-site scripting vulnerability in kortix-ai suna, published on 21 Jun 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

A weakness has been identified in kortix-ai suna up to 0.8.38. Affected by this issue is the function router.replace/router.push of the file apps/frontend/src/app/auth/page.tsx of the component Auth Endpoint. Executing a manipulation of the argument returnURL can lead to cross site scripting. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 0.8.39 can resolve this issue. This patch is called f5dec7aa0c1b8fa0125938f292c0f2430ca75f6c. It is advisable to upgrade the affected component. The researcher explains: "The issue was fixed in v0.8.39 without notifying the wider user base via a security disclosure."

Weakness: CWE-94 (Improper Control of Generation of Code), CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-12811?


## How do I fix CVE-2026-12811?

No fix has been published for CVE-2026-12811 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12811 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-12811 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12811 and fix it if it is affected.

What it is: CVE-2026-12811 is a medium-severity cross-site scripting vulnerability in kortix-ai suna, published on 21 Jun 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-12811 exists.

Affected product: kortix-ai suna. 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-2026-12811/ (Markdown: https://insights.sbomify.com/CVE-2026-12811/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12811
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12811
- OSV: https://osv.dev/vulnerability/CVE-2026-12811

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12811/
Summaries are generated and may contain mistakes; the official description above is the record.