---
id: CVE-2026-96280
title: >-
  The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O
  and allocation functions expecting gsize (32 bits on 32-bit systems), causing
  undersized allocations while subsequent operations use the original 64-bit
  size, …
summary: >-
  The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O
  and allocation functions expecting gsize (32 bits on 32-bit systems), causing
  undersized allocations while subsequent operations use the original 64-bit
  size, …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-197
vendor: Red Hat
product: flatpak
affected:
  - flatpak (all versions)
  - flatpak (all versions)
  - flatpak (all versions)
  - flatpak (all versions)
published: '2026-09-27'
updated: '2026-09-27'
sourceUpdated: '2026-09-27T21:17:04.200'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-96280'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-96280'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2539419'
    label: secalert@redhat.com
  - url: 'https://github.com/flatpak/flatpak/security/advisories/GHSA-jr92-2v97-wgvc'
    label: secalert@redhat.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-27T20:58:01.543Z'
---

## Overview

The OCI delta stream parser read sizes as guint64 but passed them to GLib I/O and allocation functions expecting gsize (32 bits on 32-bit systems), causing undersized allocations while subsequent operations use the original 64-bit size, leading to heap buffer overflows. An attacker controlling an OCI registry can craft a delta stream that triggers this during flatpak install/update, potentially achieving code execution on 32-bit systems.

## Remediation

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