# CVE-2026-111124: CFITSIO heap-based out-of-bounds read in imcompress

Source: https://junglewise.ai/threats/cve-2026-111124-cfitsio-through-4-7-0-contains-a-heap-based-out-of-bounds-read  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-15. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-111124 · Severity: medium · CVSS 6.1 · Published 2026-10-15

CFITSIO is a library used by scientific software to read and write astronomical FITS image files. A vulnerability in its image compression code allows attackers to craft a malicious FITS file that triggers a heap memory read out-of-bounds, potentially crashing applications or leaking sensitive data from memory when the file is opened and processed.

Technologies: [HEASARC CFITSIO](https://junglewise.ai/threats/technologies/cfitsio). Vendors: [HEASARC](https://junglewise.ai/threats/vendors/heasarc).

## Quick answers

**Is CVE-2026-111124 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-111124 being exploited in the wild.

**How severe is CVE-2026-111124?** Medium severity, with a CVSS score of 6.1, published 15 October 2026.

**Which products and versions are affected?** HEASARC CFITSIO through 4.7.0.

**Is there a fix for CVE-2026-111124?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-111124 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-111124?** Check whether you run HEASARC CFITSIO at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap-based out-of-bounds read exists in the imcompress.c unquantize helpers when processing FITS files with SUBTRACTIVE_DITHER_1 compression and a zero or negative ZDITHER0 seed value. The vulnerability is triggered via fits_open_file() and fits_read_pix() when reading a specially crafted FITS file, allowing attackers to read memory before the fits_rand_value table, resulting in crashes or heap content disclosure.

## Affected products

- HEASARC CFITSIO through 4.7.0

## Timeline

- 2026-10-15: disclosed

## References

- [https://github.com/](https://github.com/)
- [https://github.com/HEASARC/cfitsio](https://github.com/HEASARC/cfitsio)

## Related threats

- [CFITSIO heap out-of-bounds write in ffgcls2](https://junglewise.ai/threats/cve-2026-115504-cfitsio-through-4-7-0-contains-an-out-of-bounds-write)
- [CFITSIO heap-based out-of-bounds read in HCOMPRESS decoder](https://junglewise.ai/threats/cve-2026-111125-cfitsio-through-4-7-0-contains-a-heap-based-out-of-bounds-read)