CVE-2023-53777 erofs: kill hooked chains to avoid loops on deduplicated compressed images
A race condition in the Linux kernel EROFS filesystem can cause a deadlock and denial of service when processing specific deduplicated compressed images.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53777?
CVE-2023-53777 is a denial of service vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
erofs: kill hooked chains to avoid loops on deduplicated compressed images
After heavily stressing EROFS with several images which include a hand-crafted image of repeated patterns for more than 46 days, I found two chains could be linked with each other almost simultaneously and form a loop so that the entire loop won't be submitted. As a consequence, the corresponding file pages will remain locked forever.
It can be _only_ observed on data-deduplicated compressed images. For example, consider two chains with five pclusters in total: Chain 1: 2->3->4->5 -- The tail pcluster is 5; Chain 2: 5->1->2 -- The tail pcluster is 2.
Chain 2 could link to Chain 1 with pcluster 5; and Chain 1 could link to Chain 2 at the same time with pcluster 2.
Since hooked chains are all linked locklessly now, I have no idea how to simply avoid the race. Instead, let's avoid hooked chains completely until I could work out a proper way to fix this and end users finally tell us that it's needed to add it back.
Actually, this optimization can be found with multi-threaded workloads (especially even more often on deduplicated compressed images), yet I'm not sure about the overall system impacts of not having this compared with implementation complexity.
Which versions are affected by CVE-2023-53777?
How do I fix CVE-2023-53777?
Apply the vendor's patch.
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-2023-53777 being exploited?
There is no known exploitation of CVE-2023-53777 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53777, DEBIAN-CVE-2023-53777, GHSA-v9mq-q8m3-5r3r, UBUNTU-CVE-2023-53777.