Pillow: Heap buffer overflow saving TIFF with libtiff when tags override image size

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-128067: 0.45% estimated exploitation activity in the next 30 days; percentile 39.73 (FIRST EPSS, 2026-11-14). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

``` ============================================================================ ANT-2026-CS7N494P [high] CWE-787 memory-safety Heap buffer overflow saving TIFF with libtiff when tags override image size Location: src/libImaging/TiffDecode.c:1035 in ImagingLibTiffEncode() Commit: a707c6b21c313880d0771e54965d142dd42358b6 ============================================================================ ``` When Pillow saves an image as a compressed TIFF, size information taken from the image's metadata can make the encoder read past the end of a heap buffer. Someone who uploads an image can use this to get the server process's memory, including pointers, copied into the saved file, or to crash the process. When the metadata also enables TIFF "Predictor=2" compression, the encoder writes past the buffer instead, corrupting the heap and aborting the process. This affects applications that write TIFF through libtiff (any `compression=` other than raw) and either carry the source metadata…

Published by the source

12 Nov 2026, 23:34 UTC

Last modified by the source

12 Nov 2026, 23:45 UTC

Source last checked

13 Nov 2026, 06:20 UTC

1. Revision 2 · amended · 13 Nov 2026

   Amended from osv record GHSA-xcvg-w56q-r89m

2. Revision 1 · created · 12 Nov 2026

   Published from ghsa record GHSA-xcvg-w56q-r89m

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# Patch Next advisory brief: CVE-2026-128067

Advisory: Pillow: Heap buffer overflow saving TIFF with libtiff when tags override image size
IDs: CVE-2026-128067, GHSA-xcvg-w56q-r89m
Record: https://patchnext.com/advisories/cve-2026-128067 (revision 2, source checked 13 Nov 2026, 06:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.4)
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 < 13.0.0; 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-xcvg-w56q-r89m (GitHub-reviewed advisory GHSA-xcvg-w56q-r89m lists affected ranges: PyPI pillow >=0 <=12.3.0)
- Verified: https://osv.dev/vulnerability/GHSA-xcvg-w56q-r89m (OSV record GHSA-xcvg-w56q-r89m lists affected ranges: PyPI pillow >=0 <13.0.0 (fixed))

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