Pillow: EPS load(scale) lets Ghostscript render past the decompression bomb limit

Exploitation

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

CVSS 4.0

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

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

When an application opens an untrusted Encapsulated PostScript file and asks Pillow to render it at a larger scale, Pillow has Ghostscript produce an image several times bigger than Pillow's configured size limit allows. The size check runs only after Ghostscript has finished rendering and written the full raw image to a temporary file. An attacker who can upload a file of about 100 bytes makes each such request spend scale² times the Ghostscript rendering work and temporary disk space that the limit is meant to permit. For example, at scale 2 that is a 972 MB temporary file. The cause is in Ghostscript() in src/PIL/EpsImagePlugin.py. It multiplies the file-declared size by the caller's scale (lines 93-94) and passes the product to gs as the -g output geometry. It never calls Image.decompressionbombcheck() on the scaled size. The only check is the one Image.open() ran on the unscaled size, so a file declaring 9000×9000 passes, and load(scale=2) then asks Ghostscript for 18000×18000…

Published by the source

20 Oct 2026, 20:53 UTC

Last modified by the source

20 Oct 2026, 21:00 UTC

Source last checked

26 Oct 2026, 13:55 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-vx6w-vv9f-6gvg

2. Revision 3 · amended · 25 Oct 2026

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

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-vx6w-vv9f-6gvg

4. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-vx6w-vv9f-6gvg

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# Patch Next advisory brief: CVE-2026-112899

Advisory: Pillow: EPS load(scale) lets Ghostscript render past the decompression bomb limit
IDs: CVE-2026-112899, GHSA-vx6w-vv9f-6gvg
Record: https://patchnext.com/advisories/cve-2026-112899 (revision 4, source checked 26 Oct 2026, 13:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
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. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pillow: affected >= 2.3.0, <= 12.3.0; fixed in 13.0.0

## Suggested inspection (read-only)
- `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-vx6w-vv9f-6gvg (GitHub-reviewed advisory GHSA-vx6w-vv9f-6gvg lists affected ranges: PyPI pillow >=2.3.0 <=12.3.0)
- Verified: https://osv.dev/vulnerability/GHSA-vx6w-vv9f-6gvg (OSV record GHSA-vx6w-vv9f-6gvg lists affected ranges: PyPI pillow >=2.3.0 <13.0.0 (fixed))

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