CVE-2026-112403

Pillow: Heap buffer overflow in ImagingJpegDecode

No known exploitation. EPSS puts it in the 55th percentile. No fix published yet.

CVSS —Not scored EPSS percentile55th0.8% chance in 30 days CISA KEVNot listedNo confirmed exploitation
No public exploit known FixNone yetNo fix or workaround published

Published 2026-10-19Updated 2026-10-22Sources: CVE.org, NVD

NVD CVE.org

What to do

No fixed build or workaround is published yet. Limit exposure and watch for a patch.

python-pillow PillowAffected: < 13.0.0Upgrade to: not statedStated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

Steps

Written by AI from the record

Ask your developer or vendor whether your website, app, or internal tools use the Pillow Python library to process images (especially features that resize or create thumbnails from user-uploaded JPEGs).
If Pillow is used, check which version is installed and whether it's linked against libjpeg-turbo 3.x — this combination is required for the issue to trigger.
There is currently no officially confirmed fixed version — ask your developer to monitor Pillow's official release notes and apply an update as soon as one addressing this issue is published.
In the meantime, avoid letting untrusted users upload JPEG files that get processed through resizing/thumbnail features, or add validation before those files reach the image library.

May need vendor or contractor work

What it is

From the CVE record

Pillow is a Python imaging library. Prior to 13.0.0, Pillow's JPEG decoder can write a full-width scanline into a buffer sized for a requested draft scale. ImagingJpegDecode does not verify libjpeg's actual output width and component count after scaling is requested, and an 8-bit lossless SOF3 JPEG decoded by a build linked to libjpeg-turbo 3.x can ignore the requested downscaling geometry. An attacker can supply such a JPEG to an application that uses draft() or thumbnail() to request downscaling. This can corrupt heap memory, crash the process, or potentially allow code execution. Older libjpeg-turbo 2.x and IJG builds reject the SOF3 input. This issue is fixed in version 13.0.0.

In plain language

Written by AI from the record

This is a flaw in Pillow, a Python library many apps use to resize and process images, that could crash a program or corrupt memory when handling a specially crafted JPEG — it's not being exploited and there's no confirmed fix version yet, so most small businesses don't need to act urgently.

Heap buffer overflow in Pillow's ImagingJpegDecode occurs when an attacker supplies a crafted 8-bit lossless SOF3 JPEG to an application calling draft() or thumbnail() for downscaling, causing the JPEG decoder to write a full-width scanline into an undersized scale-reduced buffer on builds linked against libjpeg-turbo 3.x.

If you're affected

Application crash
Potential code execution
Service disruption during image processing

What is it

Pillow is like the photo-processing engine inside many websites and apps — it resizes, crops, and creates thumbnails of images people upload. This bug means a cleverly booby-trapped photo file could confuse that engine into writing data outside its intended memory space, like pouring too much liquid into a cup that then overflows onto the counter, potentially crashing the program or, in a worst case, letting an attacker run their own code.

Who is affected

This matters to you if your website, app, or internal tools use the Pillow Python library to resize images or generate thumbnails from JPEG files, particularly if those JPEGs come from users or the public internet. It only becomes a real risk if your Pillow build is linked against libjpeg-turbo 3.x and your code calls image-downscaling features like draft() or thumbnail() on untrusted files.

How urgent is it

There is no evidence anyone is exploiting this right now, no public exploit code exists, and predictions suggest it's unlikely to be weaponized soon. This is a situation to track and address during normal maintenance rather than something requiring emergency action.

What to do — in detail

Confirm exposure by identifying which services use Pillow's JPEG decoding path with draft() or thumbnail() calls on untrusted input, and check whether your Pillow build links against libjpeg-turbo 3.x (builds on libjpeg-turbo 2.x or IJG libjpeg reject the malformed SOF3 input and are not affected). No fix/patch information is currently available in our tracking data, so there is no confirmed fixed version to target yet — treat the technical description's reference to Pillow 13.0.0 as unverified until Pillow's official changelog/security advisories confirm it, and subscribe to Pillow's GitHub releases or security advisories for updates. As a temporary workaround, avoid applying draft() or thumbnail()-based downscaling to untrusted JPEG uploads, or pre-validate/re-encode images with a separate sanitizer before passing them to Pillow. Monitor for official patch announcements, CVE updates, and any libjpeg-turbo advisories, and re-test affected services once a fix is released.

Technical context

Weakness: CWE-122 (heap-based buffer overflow). Attack vector: a malicious 8-bit lossless SOF3 JPEG processed via Pillow's draft()/thumbnail() scaling path, where ImagingJpegDecode fails to validate libjpeg's actual output width/component count against the buffer sized for the requested draft scale, on builds linked against libjpeg-turbo 3.x (2.x/IJG builds reject this SOF3 input and aren't affected). Exploitation status: not in CISA KEV, no public exploit code, and EPSS places it in the lower range of predicted exploitation likelihood with a flat trend. Patch status: no fix/patch information is currently confirmed in tracking data; impact severity ranges from denial-of-service (crash) to a stated potential for code execution depending on memory layout and decoder internals.

This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.