Linux Kernel netfs Read Retry Fixes

Read retry logic in the Linux kernel's netfs subsystem can incorrectly abandon all remaining subrequests due to an uninitialized or invalid pointer, potentially exposing unintended memory contents or causing denial of service through kernel crashes. Affects Linux kernel 6.12 through early 6.19 and 7.0 development branches. Vendor patches available for 6.18.21, 6.19.11, and mainline 7.0. EPSS score of 0.02% (4th percentile) indicates low real-world exploitation probability. Not listed in CISA KEV. CVSS 8.8 reflects network attack vector with user interaction required.

NULL pointer dereference in the Linux kernel's netfs subsystem crashes the kernel when retrying unbuffered writes on filesystems that omit the prepare_write stream operation, such as 9P. A local low-privilege user who can write to such a mounted filesystem and induce a get_user_pages() -EFAULT failure can trigger a kernel panic, causing a denial of service. No public exploit has been identified at time of analysis, and the EPSS score of 0.02% (4th percentile) reflects negligible observed exploitation probability; the vulnerability is not listed in CISA KEV.