# CVE-2026-104895: The asynchronous Smile parser (NonBlockingByteArrayParser) uses a raw-binary length prefix taken from untrusted input to allocate a byte[] b


- **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
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** GHSA-h3c2-2m49-r49w

## What is CVE-2026-104895?

CVE-2026-104895 is a high-severity vulnerability in FasterXML jackson-dataformat-smile, published on 28 Oct 2026. 

### Official description

The asynchronous Smile parser (NonBlockingByteArrayParser) uses a raw-binary length prefix taken from untrusted input to allocate a byte[] before the body is read, with no upper bound and no overflow check. On the raw-binary marker 0xFD, _decodeVInt() computes (value << 6) + (i & 0x3F) without the (value >>> 25) != 0 overflow guard present in the blocking SmileParser._readUnsignedVInt, and _startRawBinary then allocates the declared length immediately.

A Smile feed of roughly ten bytes can therefore force an eager allocation of approximately 2 GB, producing an OutOfMemoryError on reactive or asynchronous Smile endpoints. A VInt crafted to overflow int yields a negative length and a NegativeArraySizeException, a RuntimeException that is not a JacksonException and so escapes the parser contract. Either outcome crashes the request or processing thread.

This is the same class of issue as CVE-2020-28491 in the CBOR parser of this library, which was fixed with a LONGEST_NON_CHUNKED_BINARY guard; the asynchronous Smile parser never received the equivalent guard. No privileges or user interaction beyond the ability to submit data for parsing are required.

Weakness: CWE-789 (Memory Allocation with Excessive Size Value)

## Which versions are affected by CVE-2026-104895?


## How do I fix CVE-2026-104895?

No fix has been published for CVE-2026-104895 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104895 being exploited?

There is no known exploitation of CVE-2026-104895 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104895 and fix it if it is affected.

What it is: CVE-2026-104895 is a high-severity vulnerability in FasterXML jackson-dataformat-smile, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-104895 in the wild and no public exploit code.

Affected product: FasterXML jackson-dataformat-smile. 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-2026-104895/ (Markdown: https://insights.sbomify.com/CVE-2026-104895/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104895
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104895
- OSV: https://osv.dev/vulnerability/CVE-2026-104895

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104895/
Summaries are generated and may contain mistakes; the official description above is the record.