---
id: CVE-2026-111125
title: >-
  CFITSIO through 4.7.0 contains a heap-based out-of-bounds read vulnerability
  in the HCOMPRESS tile decoder that allows attackers to read past the
  compressed tile buffer via input_nnybble in fits_hdecompress.c
summary: >-
  CFITSIO through 4.7.0 contains a heap-based out-of-bounds read vulnerability
  in the HCOMPRESS tile decoder that allows attackers to read past the
  compressed tile buffer via input_nnybble in fits_hdecompress.c. Attackers can
  supply a craf…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H'
cwe:
  - CWE-125
vendor: HEASARC
product: cfitsio
affected:
  - cfitsio <= 4.7.0
published: '2026-10-15'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T19:17:25.780'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-111125'
references:
  - url: 'https://github.com/HEASARC/cfitsio'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/HEASARC/cfitsio/blob/d6d27653740864a0483e74cff23c53e34e1dceee/fits_hdecompress.c#L2575-L2633
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/HEASARC/cfitsio/blob/d6d27653740864a0483e74cff23c53e34e1dceee/imcompress.c#L6310-L6316
    label: disclosure@vulncheck.com
  - url: 'https://hackmd.io/@haind-pwn/cfitsio-zdither0-dither-seed-oob-read'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/cfitsio-through-4.7.0-heap-out-of-bounds-read-via-hcompress-input-nnybble
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-15T19:25:46.406Z'
---

## Overview

CFITSIO through 4.7.0 contains a heap-based out-of-bounds read vulnerability in the HCOMPRESS tile decoder that allows attackers to read past the compressed tile buffer via input_nnybble in fits_hdecompress.c. Attackers can supply a crafted FITS file with ZCMPTYPE HCOMPRESS_1 declaring oversized tile geometry to crash applications calling fits_read_pix or disclose limited heap memory.

## Remediation

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