CVE-2026-64160

A flaw was found in the Linux kernel's network file system (netfs) component. This vulnerability, known as 'tearing', occurs when the system attempts to update file size information (remote_i_size and zero_point) without proper synchronization. This can lead to corrupted file size counters (i_size_seqcount), potentially causing data integrity issues or incorrect reporting of file sizes. An attacker could potentially exploit this to manipulate file sizes or cause system instability.

A race in netfs size handling can expose torn or inconsistent 64-bit values for remote_i_size and zero_point, especially on 32-bit systems. These fields affect decisions about the real remote file size and the point above which reads may be treated as zero filled, so inconsistent values can cause wrong I/O behavior, stale or incorrect data handling, and availability problems such as hangs or repeated seqcount retries. For the CVSS the PR:L because an unprivileged local process with access to an affected mounted netfs file can trigger concurrent I/O paths, although reliable triggering may also depend on filesystem permissions, mount configuration, and server behavior. The issue is not directly network reachable as a standalone packet attack against the kernel, but exposure is higher when network filesystem clients such as 9p, AFS, or SMB are mounted and used with concurrent local and remote size changes. Impact is at least local denial of service and possible low integrity impact.

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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.