CVE-2026-97487

A flaw was found in the Linux kernel's Journaled File System (JFS). An unhandled error when initializing the file system block size during mount operations allows a local user with mount privileges to cause a Denial of Service (DoS). By attempting to mount an incompatible or crafted storage volume, an attacker can trigger a kernel assertion failure, resulting in an immediate system crash.

A low impact denial of service flaw was found in the Linux kernel's Journaled File System (JFS) implementation. During a JFS mount, the return value of sb_set_blocksize() is not handled; when setting the superblock block size fails, for example when the underlying device presents a block size larger than PAGE_SIZE, the mount continues and the first buffer head access reaches a BUG_ON assertion in folio_set_bh(), producing a kernel Oops or panic that crashes the system. A local user with privileges to mount filesystems (typically CAP_SYS_ADMIN) can trigger this by attempting to mount a crafted or incompatible JFS volume. Only system availability is affected; there is no impact on confidentiality or integrity.

Red Hat Product Security assessed this flaw as Low impact. Although the Red Hat CVSS:3.1 score of 5.5 (Moderate) reflects the availability impact of a kernel crash, realistic exploitation requires high local privileges and control over the block device being mounted, which limits practical risk and supports the lower severity rating. No Red Hat products are currently listed as affected: the kernel packages shipped in supported Red Hat Enterprise Linux, Red Hat In-Vehicle OS, and OpenShift Container Platform releases do not contain the vulnerable code, and the Red Hat Enterprise Linux 6 Extended Life-cycle Support kernel is out of support scope.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.