Pillow tiled-TIFF decoder reads past tile buffer in copy4 (Unpack.c:1290)

Exploitation

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

CVSS

6.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

EPSS

• CVE-2026-112395: 0.51% estimated exploitation activity in the next 30 days; percentile 43.89 (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.

Summary Pillow's libImaging `_decodeTile` decoder, used to decode tiled TIFF images, allocates a per-tile buffer using `realloc(state->buffer, TIFFTileSize(tiff))`. After each `TIFFReadTile` it then iterates `tile_y` from 0 up to `current_tile_length` and calls the configured row unpacker (here `copy4`) with the source pointer `state->buffer + tile_y * row_byte_size`. When libtiff returns a `tile_bytes_size` smaller than the worst-case `row_byte_size * tile_length`, the inner stride-and-copy loop walks past the realloc'd region and `copy4` performs a 1024-byte `memcpy` that reads up to `(tile_length-1) * row_byte_size + row_byte_size` bytes from a buffer sized only to `tile_bytes_size`. The supplied PoC TIFF triggers a 1024-byte over-read exactly 0 bytes past a 196608-byte allocation. An attacker who can convince a Pillow-using application to decode a crafted TIFF can trigger a process crash (DoS) and may cause adjacent heap memory to be copied into the decoded pixel buffer. ###…

Published by the source

20 Oct 2026, 20:49 UTC

Last modified by the source

27 Oct 2026, 09:30 UTC

Source last checked

28 Oct 2026, 06:45 UTC

1. Revision 6 · amended · 28 Oct 2026

   Amended from osv record BIT-pillow-2026-112395

2. Revision 5 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-462x-pgg6-55fp

3. Revision 4 · amended · 26 Oct 2026

   Amended from osv record BIT-pillow-2026-112395

4. Revision 3 · amended · 26 Oct 2026

   Amended from osv record GHSA-462x-pgg6-55fp

5. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-462x-pgg6-55fp

6. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-462x-pgg6-55fp

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

# Patch Next advisory brief: CVE-2026-112395

Advisory: Pillow tiled-TIFF decoder reads past tile buffer in copy4 (Unpack.c:1290)
IDs: CVE-2026-112395, GHSA-462x-pgg6-55fp
Record: https://patchnext.com/advisories/cve-2026-112395 (revision 6, source checked 28 Oct 2026, 06:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
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 >= 8.2.0, < 13.0.0; fixed in 13.0.0
- PyPI pillow: affected >= 8.2.0, < 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-462x-pgg6-55fp (GitHub-reviewed advisory GHSA-462x-pgg6-55fp lists affected ranges: PyPI pillow >=8.2.0 <13.0.0)
- Verified: https://osv.dev/vulnerability/GHSA-462x-pgg6-55fp (OSV record GHSA-462x-pgg6-55fp lists affected ranges: PyPI pillow >=8.2.0 <13.0.0 (fixed))
- Verified: https://osv.dev/vulnerability/BIT-pillow-2026-112395 (OSV record BIT-pillow-2026-112395 lists affected ranges: Bitnami pillow >=8.2.0 <13.0.0 (fixed))

Commands are suggestions: review each one before running it.