# CVE-2026-112898: Pillow: Image.quantize() with empty palette leaks uninitialized stack memory

> An attacker can leak uninitialized stack memory, including addresses and canaries, by providing an empty palette to Image.quantize() in Pillow.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** BIT-pillow-2026-112898, DEBIAN-CVE-2026-112898, ECHO-40ef-e643-dc9f, GHSA-rfgq-q3w2-pmv2, UBUNTU-CVE-2026-112898

## What is CVE-2026-112898?

CVE-2026-112898 is a medium-severity vulnerability in Python Pillow, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Pillow is a Python imaging library. From 9.1.0 until 13.0.0, Pillow can disclose uninitialized stack memory when Image.quantize() uses an empty palette. ImagingPaletteCacheUpdate() leaves a local cache array uninitialized when the palette has zero entries, and the conversion path emits those bytes as output pixel indices. An attacker who controls the palette image can obtain stack contents from a returned PNG or GIF. This can disclose addresses and stack-canary data without an out-of-bounds access, memory corruption, or process crash. This issue is fixed in version 13.0.0.

Weakness: CWE-457 (Use of Uninitialized Variable)

## Which versions are affected by CVE-2026-112898?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pillow` | Bitnami | From 9.1.0 | 13.0.0 |
| `pillow` | PyPI | From 9.1.0 | 13.0.0 |
| `Pillow` | PyPI | From 9.1.0 | 13.0.0 |

Products: Python Pillow.

## How do I fix CVE-2026-112898?

Upgrade pillow to 13.0.0 or later.

## Is CVE-2026-112898 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112898 exists.

## 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-2026-112898 and fix it if it is affected.

What it is: CVE-2026-112898 is a medium-severity vulnerability in Python Pillow, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112898 exists.

Affected packages and fixed versions:
- pillow (Bitnami): affected from 9.1.0; fixed in 13.0.0
- pillow (PyPI): affected from 9.1.0; fixed in 13.0.0
- Pillow (PyPI): affected from 9.1.0; 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-2026-112898/ (Markdown: https://insights.sbomify.com/CVE-2026-112898/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-112898
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-112898
- OSV: https://osv.dev/vulnerability/CVE-2026-112898

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-112898/
Summaries are generated and may contain mistakes; the official description above is the record.