vulnerability / NVI-00010681 / Revision 2
Pillow multi-frame loaders can reuse stale native image storage after mode transitions
GitHub lists this reviewed advisory for Pillow. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
9.8 critical
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
0.659%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.51538. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
Pillow
source listed>= 11.0.0, < 13.0.0
### Summary Pillow multi-frame image loaders can retain native `ImagingCore` storage allocated for one frame while changing the Python-side image `mode` and decoder tiles for a later frame. If frame 0 allocates storage for a narrow mode such as `L`, and a later frame of the same dimensions switches to a wider mode such as `RGB` or `CMYK`, Pillow may decode wider pixels into the stale narrow native buffer. This causes native out-of-bounds writes and process crashes. In the MPO/JPEG path, I also demonstrated command execution in matching Python/Pillow runtime profiles through Pillow's documented `ImageSequence.Iterator` + `frame.load()` path. ### Details The root cause appears to be that `ImageFile.load_prepare()` only reallocates native storage when `_im is None`. It does not verify that the retained native `ImagingCore` storage still matches `self.mode` and `self.size`. Several multi-frame `seek()` / `_open()` paths can update `self._mode` and decoder tiles for a later frame without invalidating `_im`. The decoder then writes or reads according to the new frame mode while the native storage still belongs to the old frame mode. Verified affected surfaces: 1. **PSD** `PsdIma
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-v9pv-5gc8-w2m6 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-96639 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.