# CVE-2026-104016: ProtobufParser parses length-prefixed protobuf string and bytes fields by checking (_inputPtr + len) <= _inputEnd and then, on the fast path


- **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:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** GHSA-c2rq-mcfv-jw29

## What is CVE-2026-104016?

CVE-2026-104016 is a high-severity vulnerability in FasterXML jackson-dataformat-protobuf, published on 27 Oct 2026. 

### Official description

ProtobufParser parses length-prefixed protobuf string and bytes fields by checking (_inputPtr + len) <= _inputEnd and then, on the fast path, calling _finishShortText(len). Both use 32-bit signed integer arithmetic. When an attacker supplies a varint decoding to a length near Integer.MAX_VALUE, _inputPtr + len overflows to a negative value, the bounds check passes, and _finishShortText(len) reaches TextBuffer.expandCurrentSegment(len), which performs Arrays.copyOf with no cap and throws OutOfMemoryError: Requested array size exceeds VM limit.

The JVM refuses arrays larger than Integer.MAX_VALUE - 8 before consulting available heap, so -Xmx tuning does not mitigate the issue. StreamReadConstraints.maxStringLength and maxDocumentLength do not gate this path: a 33-byte payload is far below any document-length cap and the string-length check does not fire before the allocation. This was confirmed empirically against shipping artifacts with maxStringLength, maxDocumentLength and maxNestingDepth all configured.

A February 2026 hardening commit added the equivalent overflow guard to the packed-array-length and message-length paths but left the string-length call sites unguarded. No privileges or user interaction beyond the ability to submit data for parsing are required.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-104016?


## How do I fix CVE-2026-104016?

No fix has been published for CVE-2026-104016 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104016 being exploited?

There is no known exploitation of CVE-2026-104016 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104016 and fix it if it is affected.

What it is: CVE-2026-104016 is a high-severity vulnerability in FasterXML jackson-dataformat-protobuf, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-104016 in the wild and no public exploit code.

Affected product: FasterXML jackson-dataformat-protobuf. 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-2026-104016/ (Markdown: https://insights.sbomify.com/CVE-2026-104016/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104016
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104016
- OSV: https://osv.dev/vulnerability/CVE-2026-104016

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-104016/
Summaries are generated and may contain mistakes; the official description above is the record.