CVE Catalog

CVE-2026-53392

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.53%

42th percentile - higher than 42% of all known CVEs

Summary

In the Linux kernel, the NFSv4/flexfiles driver lacks validation for a zero filehandle version count. An attacker can supply a malformed flexfiles layout, causing a NULL pointer dereference and kernel panic.

Risk Assessment

The organization is at risk of system crashes (kernel panic) due to a remote attack on the NFS service, potentially disrupting critical operations.

Recommendation

Immediately update the Linux kernel to a version that includes the fix rejecting zero filehandle version counts.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: NFSv4/flexfiles: reject zero filehandle version count ff_layout_alloc_lseg() decodes the filehandle-version array count from the flexfiles layout body. The value is used as the count for kzalloc_objs(), and the current code only rejects NULL. A zero count yields ZERO_SIZE_PTR, which can be stored in dss_info->fh_versions even though later flexfiles paths assume that at least one filehandle version exists. Reject fh_count == 0 before the allocation, matching the existing zero version_count validation in the flexfiles GETDEVICEINFO parser. A QEMU/KASAN run with a malformed flexfiles layout hit: KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:ff_layout_encode_ff_layoutupdate.isra.0+0x15f/0x750 ff_layout_encode_layoutreturn+0x683/0x970 nfs4_xdr_enc_layoutreturn+0x278/0x3a0 Kernel panic - not syncing: Fatal exception The patched kernel rejects the malformed layout without KASAN/oops/panic, and a valid fh_count=1 regression still opens, reads, and unmounts cleanly.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS