---
id: CVE-2026-106554
title: >-
  jackson-dataformat-cbor: quadratic-time TagList growth on unbounded stacked
  tags (CPU/GC DoS, PoC)
summary: >-
  One CBOR-parsing issue in jackson-dataformats-binary's CBOR module: an
  unbounded run of CBOR tags drives quadratic-time TagList growth
  (CPU/GC-exhaustion DoS, PoC-proven).




  PoC executed against com.fasterxml.jackson.dataformat:jackson-…
severity: none
cwe:
  - CWE-407
vendor: FasterXML
product: 'com.fasterxml.jackson.dataformat:jackson-dataformat-cbor'
affected:
  - 'com.fasterxml.jackson.dataformat:jackson-dataformat-cbor >= 2.15.0 < 2.18.12'
  - 'com.fasterxml.jackson.dataformat:jackson-dataformat-cbor >= 2.19.0 < 2.21.8'
  - 'com.fasterxml.jackson.dataformat:jackson-dataformat-cbor >= 2.22.0 < 2.22.4'
  - 'tools.jackson.dataformat:jackson-dataformat-cbor >= 3.0.0 < 3.1.8'
  - 'tools.jackson.dataformat:jackson-dataformat-cbor >= 3.2.0 < 3.2.4'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T16:14:05.664Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-106554'
references:
  - url: >-
      https://github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA-cjg7-h3pr-p927
    label: GHSA-cjg7-h3pr-p927
tags:
  - cve.org
ingestedAt: '2026-11-05T21:36:00.451Z'
epss: 0.00177
epssPercentile: 0.07345
---

## Overview

One CBOR-parsing issue in jackson-dataformats-binary's CBOR module: an unbounded run of CBOR tags drives quadratic-time TagList growth (CPU/GC-exhaustion DoS, PoC-proven).



PoC executed against com.fasterxml.jackson.dataformat:jackson-dataformat-cbor:2.18.2; present in current 2.x and 3.x (tools.jackson.dataformat.cbor) HEAD. Distinct from the Avro and Smile/Protobuf advisories for this repo.



Quadratic CPU/GC DoS from an unbounded chain of CBOR tags (PoC-proven). File: cbor/src/main/java/.../cbor/CBORParser.java (tag handling -> TagList).



CBOR permits a data item to be preceded by any number of semantic tags. The CBOR parser accumulates them in a TagList whose backing array grows by a fixed increment (+8), not by doubling, and re-scans/copies on each growth. An attacker sends a value preceded by a long run of tag bytes; the fixed-increment growth makes accumulating N tags O(N^2) in time (plus GC pressure), with no cap on the number of stacked tags.



PoC (executed, JDK 17): feeding a CBOR stream consisting of a long run of tag bytes (e.g. tag 0xC0+) before a trivial value forces quadratic CPU/GC; parse time grows super-linearly with the tag count, pinning a request thread with no configurable limit.



Impact. Algorithmic-complexity denial of service (CWE-407): a modest input of stacked tags consumes quadratic CPU/GC, pinning a request thread; concurrent requests exhaust the pool.



Fix. Grow TagList by doubling and/or cap the number of stacked tags (StreamReadConstraints-style).

## Affected

- `com.fasterxml.jackson.dataformat:jackson-dataformat-cbor >= 2.15.0 < 2.18.12`
- `com.fasterxml.jackson.dataformat:jackson-dataformat-cbor >= 2.19.0 < 2.21.8`
- `com.fasterxml.jackson.dataformat:jackson-dataformat-cbor >= 2.22.0 < 2.22.4`
- `tools.jackson.dataformat:jackson-dataformat-cbor >= 3.0.0 < 3.1.8`
- `tools.jackson.dataformat:jackson-dataformat-cbor >= 3.2.0 < 3.2.4`

## Remediation

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