---
id: CVE-2026-122330
title: >-
  Blosc c-blosc2 before 3.5.0 Divide-by-Zero via
  blosc2_schunk_get_slice_buffer()
summary: >-
  Blosc c-blosc2 before 3.5.0 contains a divide-by-zero vulnerability in
  blosc2_schunk_get_slice_buffer() in blosc/schunk.c that allows attackers to
  crash applications by supplying crafted frames with unchecked zero chunksize
  or blocksize …
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-369
vendor: Blosc
product: c-blosc2
affected:
  - c-blosc2 < 3.5.0
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T20:42:11.695290Z'
exploitAvailable: true
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:42:34.933Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-122330'
references:
  - url: 'https://github.com/Blosc/c-blosc2/issues/834'
  - url: >-
      https://github.com/Blosc/c-blosc2/commit/4fff1787408d94b895c6f9cb50f7925ad5919052
  - url: 'https://github.com/Blosc/c-blosc2/blob/v3.4.1/blosc/schunk.c#L1662-L1700'
  - url: 'https://github.com/Blosc/c-blosc2/blob/v3.4.1/blosc/frame.c#L1214-L1227'
  - url: 'https://hackmd.io/@haindpwn/c-blosc2-schunk-slice-divide-by-zero'
  - url: 'https://github.com/Blosc/c-blosc2'
  - url: >-
      https://www.vulncheck.com/advisories/blosc-c-blosc2-before-3.5.0-divide-by-zero-via-blosc2-schunk-get-slice-buffer
    label: >-
      VulnCheck Advisory: Blosc c-blosc2 before 3.5.0 Divide-by-Zero via
      blosc2_schunk_get_slice_buffer()
tags:
  - cve.org
  - exploit-available
ingestedAt: '2026-11-05T22:38:31.874Z'
epss: 0.00237
epssPercentile: 0.14831
---

## Overview

Blosc c-blosc2 before 3.5.0 contains a divide-by-zero vulnerability in blosc2_schunk_get_slice_buffer() in blosc/schunk.c that allows attackers to crash applications by supplying crafted frames with unchecked zero chunksize or blocksize values. Attackers can provide a malicious Blosc2 frame opened via blosc2_schunk_open() or blosc2_schunk_from_buffer() and read as a slice, raising SIGFPE and terminating the process.

## Affected

- `c-blosc2 < 3.5.0`

## Remediation

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