Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 7.1amended

Pillow: PNG eXIf chunk makes EXIF parsing run in quadratic time

CVE-2026-96643GHSA-g4qv-2jxx-769h

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (pillow 13.0.0; pillow 13.0.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

  • Bitnami pillow

    Affected
    >= 11.0.0, < 13.0.0
    Fixed in
    13.0.0

  • PyPI pillow

    Affected
    >= 11.0.0, < 13.0.0
    Fixed in
    13.0.0

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
7.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2026-96643: 0.37% estimated exploitation activity in the next 30 days; percentile 31.31 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary A PNG file with a large eXIf chunk full of repeated 6-byte markers makes Pillow's EXIF parser take seconds of CPU instead of milliseconds. The cost grows with the square of the chunk size, so a normal small-photo-sized file is enough to cause real delay.

Details `Exif.load()` in `src/PIL/Image.py` strips a marker from the start of the EXIF data like this: ```python while data and data.startswith(b"Exif\x00\x00"): data = data[6:] ``` Each pass makes a new copy of the remaining data. A real camera writes this marker once, so this is not normally a problem. `chunk_eXIf()` in `src/PIL/PngImagePlugin.py` puts the raw PNG eXIf chunk straight into `info["exif"]` with no size limit and no check of its content. PNG text chunks (tEXt, zTXt, iTXt) are capped with `MAX_TEXT_CHUNK` and `MAX_TEXT_MEMORY`. The eXIf chunk has no such cap. If the eXIf chunk is filled with repeated `Exif\x00\x00` markers instead of real EXIF data, the strip loop runs once per marker, copying a large…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 10 · amended ·

    Amended from osv record BIT-pillow-2026-96643

  2. Revision 9 · amended ·

    Amended from osv record PYSEC-2026-4342

  3. Revision 8 · amended ·

    Amended from osv record GHSA-g4qv-2jxx-769h

  4. Revision 7 · amended ·

    Amended from osv record PYSEC-2026-4342

  5. Revision 6 · amended ·

    Amended from osv record GHSA-g4qv-2jxx-769h

  6. Revision 5 · amended ·

    Amended from ghsa record GHSA-g4qv-2jxx-769h

  7. Revision 4 · amended ·

    Amended from ghsa record GHSA-g4qv-2jxx-769h

  8. Revision 3 · amended ·

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

  9. Revision 2 · amended ·

    Amended from osv record GHSA-g4qv-2jxx-769h

  10. Revision 1 · created ·

    Published from ghsa record GHSA-g4qv-2jxx-769h

Agent brief

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

# Patch Next advisory brief: CVE-2026-96643

Advisory: Pillow: PNG eXIf chunk makes EXIF parsing run in quadratic time
IDs: CVE-2026-96643, GHSA-g4qv-2jxx-769h
Record: https://patchnext.com/advisories/cve-2026-96643 (revision 10, 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 7.1)
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 >= 11.0.0, < 13.0.0; fixed in 13.0.0
- PyPI pillow: affected >= 11.0.0, < 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-g4qv-2jxx-769h (GitHub-reviewed advisory GHSA-g4qv-2jxx-769h lists affected ranges: PyPI pillow >=11.0.0 <13.0.0)
- Verified: https://osv.dev/vulnerability/GHSA-g4qv-2jxx-769h (OSV record GHSA-g4qv-2jxx-769h lists affected ranges: PyPI pillow >=11.0.0 <13.0.0 (fixed))
- Verified: https://osv.dev/vulnerability/PYSEC-2026-4342 (OSV record PYSEC-2026-4342 lists affected ranges: PyPI pillow >=11.0.0 <13.0.0 (fixed))
- Verified: https://osv.dev/vulnerability/BIT-pillow-2026-96643 (OSV record BIT-pillow-2026-96643 lists affected ranges: Bitnami pillow >=11.0.0 <13.0.0 (fixed))

Commands are suggestions: review each one before running it.

Loading voting…