CVE-2026-74579

Status: UPDATED  |  Advisory ID: CVE-2026-74579

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nft_payload: fix mask build for partial field offload

nft_payload_offload_mask() builds the offload match mask for a payload

expression that covers only part of a header field. For a partial IPv6

address match (field_len = 16, priv_len = 1) that shift is 1 << 120, which

is undefined on the 32-bit int operand. It also trims only one word, so

the remaining words stay 0xffffffff (and when priv_len is a multiple of 4

the trim is skipped entirely), leaving the mask covering more bytes than

the rule matches.

UBSAN: shift-out-of-bounds in net/netfilter/nft_payload.c:278:20

shift exponent 120 is too large for 32-bit type 'int'

...

The match is byte-granular and struct nft_data is zero-initialised, so the

correct mask is simply the first priv_len bytes set to 0xff. Set those

bytes directly and drop the word/shift trimming; this removes the undefined

shift and no longer over-masks the trailing bytes. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References