CVE-2025-37779: 
Linux Ubuntu vulnerability analysis and mitigation

CVE-2025-37779 is a vulnerability discovered in the Linux kernel's lib/iov_iter component, specifically related to folio refcount handling. The vulnerability was disclosed on May 1, 2025, affecting the Linux kernel's handling of EROFS file-backed mount over v9fs on qemu (NVD, Wiz).

The vulnerability stems from a refcount handling issue where pages in bvec are coalesced across a folio boundary. The root cause is that the refcount of all non-slab folios is not properly increased, which prevents p9releaspages from correctly putting them. This leads to a bad page state condition that manifests as a page sanity check failure with a refcount of 0. The CVSS v3.1 Base Score is reported as 5.5 with a vector of CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (Red Hat).

The vulnerability can result in memory corruption through a Use-After-Free (UAF) condition, potentially leading to system instability or crashes. This is evidenced by the reported page sanity check failures and kernel dumps when the issue is triggered (Wiz).

The vulnerability has been resolved in the Linux kernel through a fix that properly increases the refcount of non-slab folios. Users should update their Linux kernel to a version that includes this fix (Wiz).