# CVE-2026-12862: XLSX formula injection in exports

> Attackers can inject malicious formulas into Excel exports, potentially compromising the environment of administrators who open the files.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:L/SA: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:** 22 Jun 2026
- **Updated:** 22 Jun 2026

## What is CVE-2026-12862?

CVE-2026-12862 is a medium-severity code injection vulnerability in pretix Venueless, published on 22 Jun 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

Untrusted user data was passed verbatim to Excel exports for administrators. This allowed formula injection which can be used to compromise the environment of the user loading the file or other data in the file.

Weakness: CWE-148 (Improper Neutralization of Input Leaders)

## Which versions are affected by CVE-2026-12862?


## How do I fix CVE-2026-12862?

No fix has been published for CVE-2026-12862 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12862 being exploited?

There is no known exploitation of CVE-2026-12862 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12862 and fix it if it is affected.

What it is: CVE-2026-12862 is a medium-severity code injection vulnerability in pretix Venueless, published on 22 Jun 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-2026-12862 in the wild and no public exploit code.

Affected product: pretix Venueless. 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-2026-12862/ (Markdown: https://insights.sbomify.com/CVE-2026-12862/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12862
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12862
- OSV: https://osv.dev/vulnerability/CVE-2026-12862

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-12862/
Summaries are generated and may contain mistakes; the official description above is the record.