# CVE-2026-114501: Pillow: Arrow export leaks stale heap memory when PILLOW_ALIGNMENT > 1


- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 21 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** BIT-pillow-2026-114501, CLSA-2026-1793101237, DEBIAN-CVE-2026-114501, ECHO-260c-4537-5719, GHSA-654x-cwwv-5j9c, PYSEC-2026-4336, UBUNTU-CVE-2026-114501

## What is CVE-2026-114501?

CVE-2026-114501 is a medium-severity vulnerability in Python Pillow, published on 21 Oct 2026. 

### Official description

Pillow is a Python imaging library. From 11.2.1 until 13.0.0, Arrow export assumes that an image's rows are tightly contiguous and exports from im->blocks[0].ptr even when PILLOW_ALIGNMENT makes aligned_linesize include row padding or an aligned offset before the first row. The resulting Arrow buffer can include uninitialized padding, bytes preceding the first row, or stale heap contents from previously freed images. Applications that configure alignment and export images to Arrow can therefore disclose one user's pixels or other process memory to another user. This issue is fixed in version 13.0.0.

Weakness: CWE-908 (Use of Uninitialized Resource), CWE-226 (Sensitive Information in Resource Not Removed Before Reuse)

## Which versions are affected by CVE-2026-114501?

4 open source packages ship an affected version, including pillow and Pillow. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pillow` | Bitnami | From 11.2.1 | 13.0.0 |
| `pillow` | PyPI | From 11.2.1 | 13.0.0 |
| `pillow` | PyPI | From 11.2.1 | 13.0.0 |
| `Pillow` | PyPI | From 11.2.1 | 13.0.0 |

Products: Python Pillow.

## How do I fix CVE-2026-114501?

Upgrade pillow to 13.0.0 or later.

## Is CVE-2026-114501 being exploited?

There is no known exploitation of CVE-2026-114501 in the wild and no public exploit code.

## Other vulnerabilities in Python Pillow

- [CVE-2014-3007](https://insights.sbomify.com/CVE-2014-3007/): Pillow command injection (critical 10.0)
- [CVE-2026-96639](https://insights.sbomify.com/CVE-2026-96639/): Pillow multi-frame loaders can reuse stale native image storage after mode transitions (critical 9.8)
- [CVE-2022-30595](https://insights.sbomify.com/CVE-2022-30595/): Buffer over-flow in Pillow (critical 9.8)
- [CVE-2021-25289](https://insights.sbomify.com/CVE-2021-25289/): Out of bounds write in Pillow (critical 9.8)
- [CVE-2016-4009](https://insights.sbomify.com/CVE-2016-4009/): Pillow Integer overflow in ImagingResampleHorizontal (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-114501 and fix it if it is affected.

What it is: CVE-2026-114501 is a medium-severity vulnerability in Python Pillow, published on 21 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-114501 in the wild and no public exploit code.

Affected packages and fixed versions:
- pillow (Bitnami): affected from 11.2.1; fixed in 13.0.0
- pillow (PyPI): affected from 11.2.1; fixed in 13.0.0
- pillow (PyPI): affected from 11.2.1; fixed in 13.0.0
- Pillow (PyPI): affected from 11.2.1; fixed in 13.0.0

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-2026-114501/ (Markdown: https://insights.sbomify.com/CVE-2026-114501/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-114501
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114501
- OSV: https://osv.dev/vulnerability/CVE-2026-114501

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-114501/
Summaries are generated and may contain mistakes; the official description above is the record.