CVE-2026-53392
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.53%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.53% probability · 43th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/18cc6d57a14fa65ab2a2b52279f549041c4bc9cfPatch
- https://git.kernel.org/stable/c/2131ed64b767ffa8bcdb3677d90f3964e39aabc8Patch
- https://git.kernel.org/stable/c/2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2Patch
- https://git.kernel.org/stable/c/7779c85028a0676fb190cde4f0c540f4f8e97761Patch
- https://git.kernel.org/stable/c/9033591535c066726f5b505126ccb4068b98fa4fPatch
- https://git.kernel.org/stable/c/be7829715e341b42846437dd9e721005db59f0ccPatch
- https://git.kernel.org/stable/c/d8c90c7cc061265d5f2813a1f5c82ef2f4707e67Patch
- https://git.kernel.org/stable/c/eeabb9020721db6bc132e68eeae380b8d4fb4b04Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.