# CVE-2026-112396: Pillow: Heap use-after-free when encoding TIFF to an in-memory buffer

> A heap use-after-free in Pillow allows attackers to crash the process or potentially execute code by saving malicious TIFF tags to an in-memory buffer.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 20 Oct 2026
- **Also known as:** BIT-pillow-2026-112396, DEBIAN-CVE-2026-112396, ECHO-a3cb-3fc2-be43, GHSA-4rr5-89j8-mwwm, PYSEC-2026-4328, UBUNTU-CVE-2026-112396

## What is CVE-2026-112396?

CVE-2026-112396 is a medium-severity use after free 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 11.3.0 until 13.0.0, Pillow has a heap use-after-free when libtiff rejects a tag while encoding TIFF data to an in-memory buffer. When an application saves attacker-influenced TIFF tags to BytesIO, libtiff can reject a tag during encoding in ImagingLibTiffEncode; the error path then frees the output buffer without closing or clearing the TIFF handle, and later cleanup flushes through the write callback into freed memory, which can crash the process and may enable code execution. This issue is fixed in version 13.0.0.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-112396?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `pillow` | Bitnami | From 11.3.0 | 13.0.0 |
| `pillow` | PyPI | From 11.3.0 | 13.0.0 |
| `pillow` | PyPI | From 11.3.0 | 13.0.0 |
| `pillow` | PyPI | From 11.3.0 | 13.0.0 |

Products: Python Pillow.

## How do I fix CVE-2026-112396?

Upgrade pillow to 13.0.0 or later.

## Is CVE-2026-112396 being exploited?

There is no known exploitation of CVE-2026-112396 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-2026-112396 and fix it if it is affected.

What it is: CVE-2026-112396 is a medium-severity use after free 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: There is no known exploitation of CVE-2026-112396 in the wild and no public exploit code.

Affected packages and fixed versions:
- pillow (Bitnami): affected from 11.3.0; fixed in 13.0.0
- pillow (PyPI): affected from 11.3.0; fixed in 13.0.0
- pillow (PyPI): affected from 11.3.0; fixed in 13.0.0
- pillow (PyPI): affected from 11.3.0; 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-2026-112396/ (Markdown: https://insights.sbomify.com/CVE-2026-112396/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-112396
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-112396
- OSV: https://osv.dev/vulnerability/CVE-2026-112396

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-112396/
Summaries are generated and may contain mistakes; the official description above is the record.