# CVE-2026-110259: OW2 ASM 3.0 before 9.11 Uncontrolled Recursion via ClassWriter.replaceAsmInstructions()

> Attackers can cause denial of service in applications using OW2 ASM by supplying crafted class files that trigger uncontrolled recursion.

- **Severity:** Medium 6.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-110259, GHSA-g9hx-mj27-r452, UBUNTU-CVE-2026-110259

## What is CVE-2026-110259?

CVE-2026-110259 is a medium-severity denial of service vulnerability in OW2 ASM, published on 14 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

OW2 ASM 3.0 before 9.11 contains an uncontrolled recursion vulnerability in ClassWriter.replaceAsmInstructions() that allows attackers to cause denial of service through crafted class files. Attackers can supply a class with a large method containing many long forward jumps, triggering unbounded toByteArray() recursion and a StackOverflowError during transformation.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-110259?


## How do I fix CVE-2026-110259?

Upgrade to a fixed version.

## Is CVE-2026-110259 being exploited?

There is no known exploitation of CVE-2026-110259 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110259 and fix it if it is affected.

What it is: CVE-2026-110259 is a medium-severity denial of service vulnerability in OW2 ASM, published on 14 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-110259 in the wild and no public exploit code.

Affected product: OW2 ASM. 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-2026-110259/ (Markdown: https://insights.sbomify.com/CVE-2026-110259/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110259
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110259
- OSV: https://osv.dev/vulnerability/CVE-2026-110259

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-110259/
Summaries are generated and may contain mistakes; the official description above is the record.