CVE-2026-53218

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < 8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6affected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < 19748967d59c31d24d21d40b728570788310b237affected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < 46fc15a044e9938e7ea77786fb37edd2cd74f031affected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < cd513e43b4b2bd1de39e2367bc4261c699a8652faffected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < 67b27434c43b68a97becda98c9f0c8cf6cba2134affected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < 78069a6d8bc86c9e036eb82c2af4a19cc1871a53affected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265affected
LinuxLinuxc078ca3b0c5bf82c2b31906c446d6e2ad8ea0783 < 772cecf198da732faebb5dcfc46d66a505be8495affected
LinuxLinux4.11affected
LinuxLinux0 < 4.11unaffected
LinuxLinux5.10.259 <= 5.10.*unaffected
LinuxLinux5.15.210 <= 5.15.*unaffected
LinuxLinux6.1.176 <= 6.1.*unaffected
LinuxLinux6.6.143 <= 6.6.*unaffected
LinuxLinux6.12.94 <= 6.12.*unaffected
LinuxLinux6.18.36 <= 6.18.*unaffected
LinuxLinux7.0.13 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References