Pillow: Heap buffer overflow writing JPEG comment after ICC profile fills buffer

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.7 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-96778: 0.45% estimated exploitation activity in the next 30 days; percentile 39.48 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

``` ============================================================================ Heap buffer overflow writing JPEG comment after ICC profile fills buffer Location: src/libImaging/JpegEncode.c:330 in ImagingJpegEncode() Commit: a707c6b21c313880d0771e54965d142dd42358b6 ============================================================================ ``` A heap buffer overflow in Pillow's JPEG encoder lets anyone who can supply an image write up to 64 KB of bytes they choose, followed by the rest of the compressed image, past the end of a 64 KB heap buffer. The target is any application that re-saves the image as JPEG while keeping its colour profile. The reliable result is that the Python process is killed outright rather than raising an exception. Because the overwritten memory sits directly in front of function pointers that the encoder calls next, this could allow code execution, though the attached reproducer demonstrates only the crash. The bug is in `ImagingJpegEncode()` in…

Published by the source

22 Oct 2026, 16:05 UTC

Last modified by the source

29 Oct 2026, 10:56 UTC

Source last checked

30 Oct 2026, 07:20 UTC

1. Revision 7 · amended · 30 Oct 2026

   Amended from osv record BIT-pillow-2026-96778

2. Revision 6 · amended · 30 Oct 2026

   Amended from osv record GHSA-g7cr-3p24-7wf7

3. Revision 5 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-g7cr-3p24-7wf7

4. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-g7cr-3p24-7wf7

5. Revision 3 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

6. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-g7cr-3p24-7wf7

7. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-g7cr-3p24-7wf7

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-96778

Advisory: Pillow: Heap buffer overflow writing JPEG comment after ICC profile fills buffer
IDs: CVE-2026-96778, GHSA-g7cr-3p24-7wf7
Record: https://patchnext.com/advisories/cve-2026-96778 (revision 7, source checked 30 Oct 2026, 07:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: pillow 13.0.0; pillow 13.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Bitnami pillow: affected >= 9.4.0, < 13.0.0; fixed in 13.0.0
- PyPI pillow: affected >= 9.4.0, < 13.0.0; fixed in 13.0.0

## Suggested inspection (read-only)
- Bitnami pillow: check the installed version with your package manager.
- `python -m pip show pillow`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pillow.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-g7cr-3p24-7wf7 (GitHub-reviewed advisory GHSA-g7cr-3p24-7wf7 lists affected ranges: PyPI pillow >=9.4.0 <13.0.0)
- Verified: https://osv.dev/vulnerability/GHSA-g7cr-3p24-7wf7 (OSV record GHSA-g7cr-3p24-7wf7 lists affected ranges: PyPI pillow >=9.4.0 <13.0.0 (fixed))
- Verified: https://osv.dev/vulnerability/BIT-pillow-2026-96778 (OSV record BIT-pillow-2026-96778 lists affected ranges: Bitnami pillow >=9.4.0 <13.0.0 (fixed))

Commands are suggestions: review each one before running it.