CVE-2026-77467 Lychee: A single 383-byte PDF causes ~184 seconds of CPU consumption in the real processing path
Authenticated users can cause significant CPU exhaustion and service delays by uploading small PDFs with oversized dimensions, impacting web workers or processing queues.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77467?
CVE-2026-77467 is a high-severity denial of service vulnerability in LycheeOrg Lychee, published on 15 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Lychee is a free, open-source photo-management tool. Prior to 7.7.0, Lychee enables ImageMagick PDF support with Ghostscript but does not apply an effective pre-render limit to PDF page dimensions in ImagickHandler::loadPdf(). An authenticated user who can upload a small PDF with an oversized /MediaBox can cause Imagick::readImage() to consume substantial CPU before failing to produce an image. When QUEUE_CONNECTION selects synchronous processing the request can occupy a web worker, while the official asynchronous Docker configuration can clog the shared image-processing queue and delay other work. The advisory did not identify a Ghostscript sandbox escape. This issue is fixed in version 7.7.0.
Which versions are affected by CVE-2026-77467?
How do I fix CVE-2026-77467?
No fix has been published for CVE-2026-77467 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-77467 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77467 exists.
Sources
Also known as GHSA-6736-fhxv-3p79.