The vulnerability is a boundary‑check flaw in the Linux kernel’s ext4 directory handling code. A crafted directory entry whose name ends on a block boundary passes the initial length test but causes the hash trailer to be read past the block end, producing an out-of-bounds read that KASAN reports as a use-after-free. This flaw can crash the kernel and may allow privilege escalation if an attacker can trigger the fault from a controlled directory lookup.

All Linux systems running a kernel version prior to the patch that added bounds verification for hash trailers in ext4 directory entries are affected. No specific vendor or version is listed, so any kernel installation is potentially vulnerable until the fix is applied.

The vulnerability is a classic out-of-bounds read that can result in a kernel crash and possible elevation of privilege. The EPSS score is <1% and the entry is not listed in the CISA KEV catalog, indicating low current exploitation probability but serious impact if exploited. The attack vector is inferred to be local, requiring an attacker to create a malicious directory entry to trigger a lookup operation. No confirmed exploitation activity is reported in the available data.