CVE-2026-53218

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_exthdr: fix register tracking for F_PRESENT flag nft_exthdr_init() passes user-controlled priv->len to nft_parse_register_store(), which marks that many bytes in the register bitmap as initialized. However, when NFT_EXTHDR_F_PRESENT is set, the eval paths write only 1 byte (nft_reg_store8) or 4 bytes (*dest = 0 on TCP/DCCP error path). When len > 4, registers beyond the first are never written, retaining uninitialized stack data from nft_regs. Bail out if userspace requests too much data when F_PRESENT is set.

• linux linux kernel (>= 4.11 < 5.10.259) • linux linux kernel (>= 5.11 < 5.15.210) • linux linux kernel (>= 5.16 < 6.1.176) • linux linux kernel (>= 6.2 < 6.6.143) • linux linux kernel (>= 6.7 < 6.12.94) • linux linux kernel (>= 6.13 < 6.18.36) • linux linux kernel (>= 6.19 < 7.0.13) • linux linux kernel 7.1