# CVE-2026-122096: Apache DataSketches Java: Uncontrolled resource consumption when deserializing crafted sketch images

> Crafted serialized sketches can exhaust memory or cause infinite loops in applications deserializing untrusted sketches with Apache DataSketches Java.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Harmful if only installed:** No
- **Needs a specific call:** Yes (`FrequentLongsSketch.getInstance`)
- **Fix available:** No
- **Published:** 11 Nov 2026
- **Updated:** 11 Nov 2026
- **Also known as:** GHSA-jghc-rj2j-x37x

## What is CVE-2026-122096?

CVE-2026-122096 is a denial of service vulnerability in Apache DataSketches Java, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Uncontrolled Resource Consumption vulnerability in the sketch deserialization of Apache DataSketches Java.

Several deserializers trusted sizes and counts declared in the serialized input. A small crafted input could make an application allocate an excessive amount of memory, leading to an OutOfMemoryError. A crafted string passed to FrequentLongsSketch.getInstance(String) could also make deserialization, or a later update, loop indefinitely. Only applications that deserialize sketches from untrusted sources are affected.

This issue affects Apache DataSketches Java: through 9.0.0.

Users are recommended to upgrade to version 9.1.0, which fixes the issue.

Weakness: CWE-835 (Loop with Unreachable Exit Condition), CWE-789 (Memory Allocation with Excessive Size Value), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-122096?

An affected version is only exploitable if your software calls FrequentLongsSketch.getInstance. Many projects that include it are not exposed.


## How do I fix CVE-2026-122096?

No fix has been published for CVE-2026-122096 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-122096 being exploited?

There is no known exploitation of CVE-2026-122096 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-122096 and fix it if it is affected.

What it is: CVE-2026-122096 is a denial of service vulnerability in Apache DataSketches Java, published on 11 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-122096 in the wild and no public exploit code.
Exposure: An affected version is only exploitable if your software calls FrequentLongsSketch.getInstance. Many projects that include it are not exposed.

Affected product: Apache DataSketches Java. 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.
   If an affected version is present, also search the code for calls to FrequentLongsSketch.getInstance and report whether any exist.
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-2026-122096/ (Markdown: https://insights.sbomify.com/CVE-2026-122096/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-122096
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-122096
- OSV: https://osv.dev/vulnerability/CVE-2026-122096

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-122096/
Summaries are generated and may contain mistakes; the official description above is the record.