# CVE-2026-124439: Scriban before 7.5.3 Denial of Service via Uncatchable StackOverflowException


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 8 Nov 2026
- **Updated:** 10 Nov 2026
- **Also known as:** GHSA-42c9-wc59-xmx4, GHSA-mvmw-9jxc-7pr2

## What is CVE-2026-124439?

CVE-2026-124439 is a high-severity vulnerability in scriban, published on 8 Nov 2026. 

### Official description

Scriban and Scriban.Signed before 7.5.3 contain uncontrolled recursion flaws in which postfix member, indexer, and call chains bypass ExpressionDepthLimit, array comparison lacks depth and cycle checks, and object.eval bypasses RecursiveLimit. Attackers who can supply templates can trigger an uncatchable StackOverflowException that terminates the host process.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-124439?


## How do I fix CVE-2026-124439?

No fix has been published for CVE-2026-124439 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-124439 being exploited?

There is no known exploitation of CVE-2026-124439 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-124439 and fix it if it is affected.

What it is: CVE-2026-124439 is a high-severity vulnerability in scriban, published on 8 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-124439 in the wild and no public exploit code.

Affected product: scriban. 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-2026-124439/ (Markdown: https://insights.sbomify.com/CVE-2026-124439/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-124439
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-124439
- OSV: https://osv.dev/vulnerability/CVE-2026-124439

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-124439/
Summaries are generated and may contain mistakes; the official description above is the record.