# CVE-2026-111124: CFITSIO through 4.7.0 Heap Out-of-Bounds Read via Negative ZDITHER0 Seed

> Attackers can read heap memory or crash applications by supplying crafted FITS files with negative seeds to the CFITSIO library.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 15 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** AZL-108260, DEBIAN-CVE-2026-111124, ECHO-752d-aa7f-bd9e, GHSA-9mqr-56x7-4gm4, UBUNTU-CVE-2026-111124

## What is CVE-2026-111124?

CVE-2026-111124 is a medium-severity memory corruption vulnerability in HEASARC cfitsio, published on 15 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

CFITSIO through 4.7.0 contains a heap-based out-of-bounds read vulnerability in the imcompress.c unquantize helpers that allows attackers to read memory before the fits_rand_value table via a zero or negative ZDITHER0 seed. Attackers can supply a crafted FITS file with a SUBTRACTIVE_DITHER_1 compressed image, read through fits_open_file() and fits_read_pix(), to cause crashes or leak heap contents in decoded pixels.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-111124?

It affects 1 product.


Products: Nasa Cfitsio.

## How do I fix CVE-2026-111124?

Upgrade to a fixed version.

## Is CVE-2026-111124 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111124 exists.

## Other vulnerabilities in HEASARC cfitsio

- [CVE-2019-1010060](https://insights.sbomify.com/CVE-2019-1010060/): Memory corruption in CFITSIO (critical 9.8)
- [CVE-2018-3847](https://insights.sbomify.com/CVE-2018-3847/): Memory corruption in CFITSIO (high 8.8)
- [CVE-2026-111125](https://insights.sbomify.com/CVE-2026-111125/): CFITSIO through 4.7.0 Heap Out-of-Bounds Read via HCOMPRESS input_nnybble (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111124 and fix it if it is affected.

What it is: CVE-2026-111124 is a medium-severity memory corruption vulnerability in HEASARC cfitsio, published on 15 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111124 exists.

Affected product: HEASARC cfitsio. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-111124/ (Markdown: https://insights.sbomify.com/CVE-2026-111124/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111124
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111124
- OSV: https://osv.dev/vulnerability/CVE-2026-111124

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111124/
Summaries are generated and may contain mistakes; the official description above is the record.