# CVE-2026-89059: Resteasy-core: resteasy: iioimageprovider unbounded image decode (decompression-bomb dos)

> Remote attackers can cause denial of service in applications using RESTEasy by sending crafted images that trigger excessive memory allocation.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Sep 2026
- **Updated:** 29 Oct 2026
- **Also known as:** CLEANSTART-2026-XI97037, DEBIAN-CVE-2026-89059, GHSA-m4pc-7gc7-9vw2, UBUNTU-CVE-2026-89059

## What is CVE-2026-89059?

CVE-2026-89059 is a high-severity denial of service vulnerability in Red Hat Build of Keycloak, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in RESTEasy's IIOImageProvider, which decodes attacker-supplied image request bodies without enforcing any limit on the declared image dimensions or pixel count. A remote, unauthenticated attacker can send a small crafted image declaring enormous dimensions to trigger a very large memory allocation, exhausting the JVM heap and resulting in a denial of service.

Weakness: CWE-409 (Improper Handling of Highly Compressed Data (Data Amplification))

## Which versions are affected by CVE-2026-89059?


## How do I fix CVE-2026-89059?

Apply the vendor's patch.

## Is CVE-2026-89059 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89059 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89059 and fix it if it is affected.

What it is: CVE-2026-89059 is a high-severity denial of service vulnerability in Red Hat Build of Keycloak, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-89059 exists.

Affected product: Red Hat Build of Keycloak. 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-2026-89059/ (Markdown: https://insights.sbomify.com/CVE-2026-89059/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89059
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89059
- OSV: https://osv.dev/vulnerability/CVE-2026-89059

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89059/
Summaries are generated and may contain mistakes; the official description above is the record.