---
id: CVE-2026-110747
title: >-
  jackson-dataformat-protobuf: integer overflow in
  ProtobufParser._readStringKey() allows OutOfMemoryError from an 8-byte payload
summary: >-
  ProtobufParser._readStringKey() reads the length prefix of a protobuf map
  entry's string key into an attacker-controlled int and then checks (_inputPtr
  + len) <= _inputEnd using signed arithmetic. For values near Integer.MAX_VALUE
  the ad…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-190
vendor: FasterXML
product: 'com.fasterxml.jackson.dataformat:jackson-dataformat-protobuf'
affected:
  - >-
    com.fasterxml.jackson.dataformat:jackson-dataformat-protobuf >= 2.21.6 <
    2.21.8
  - >-
    com.fasterxml.jackson.dataformat:jackson-dataformat-protobuf >= 2.22.0 <
    2.22.4
  - 'tools.jackson.dataformat:jackson-dataformat-protobuf >= 3.1.6 < 3.1.8'
  - 'tools.jackson.dataformat:jackson-dataformat-protobuf >= 3.2.2 < 3.2.4'
published: '2026-10-28'
updated: '2026-10-28'
sourceUpdated: '2026-10-28T00:02:32.462Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-110747'
references:
  - url: >-
      https://github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA-fv7v-rrmh-4qcv
    label: GHSA-fv7v-rrmh-4qcv
tags:
  - cve.org
ingestedAt: '2026-10-28T01:01:24.227Z'
---

## Overview

ProtobufParser._readStringKey() reads the length prefix of a protobuf map entry's string key into an attacker-controlled int and then checks (_inputPtr + len) <= _inputEnd using signed arithmetic. For values near Integer.MAX_VALUE the addition overflows to a negative value and the check passes even when the input contains no key data. The parser then calls _finishShortText(len), which expands the text buffer to the declared length via TextBuffer.expandCurrentSegment and Arrays.copyOf, throwing OutOfMemoryError: Requested array size exceeds VM limit.



An 8-byte malformed message containing a map entry with a declared key length of 0x7FFFFFFF is sufficient. Configured StreamReadConstraints, including maxStringLength, maxNameLength, maxDocumentLength and maxNestingDepth, do not prevent the failure. Applications running with -XX:+ExitOnOutOfMemoryError terminate the JVM.



This is the same integer-overflow pattern addressed for other call sites in the remediation associated with CVE-2026-104016 and CVE-2026-104017; the map-key call site was corrected on the 3.x branches only, leaving the corresponding 2.x branches unguarded. Release lines 2.18, 2.19 and 2.20 do not contain _readStringKey() and are not affected by this vector. No privileges or user interaction beyond the ability to submit data for parsing are required. The 3.0 release line and 3.1.0-3.1.5 / 3.2.0-3.2.1 do not contain _readStringKey() and are therefore not affected; the method first appears in 3.1.6 and 3.2.2, mirroring its introduction at 2.21.6 on the 2.x side.

## Affected

- `com.fasterxml.jackson.dataformat:jackson-dataformat-protobuf >= 2.21.6 < 2.21.8`
- `com.fasterxml.jackson.dataformat:jackson-dataformat-protobuf >= 2.22.0 < 2.22.4`
- `tools.jackson.dataformat:jackson-dataformat-protobuf >= 3.1.6 < 3.1.8`
- `tools.jackson.dataformat:jackson-dataformat-protobuf >= 3.2.2 < 3.2.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.