CVE-2026-53218
Full vulnerability record from the local CVENow database.
Description
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.
Severity
MEDIUM
CVSS score
5.5
(v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-25 09:16:39.500000
Last modified
2026-11-06 17:18:14.390000
View original CVE JSON
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-06-25T09:16:39.500",
"lastModified": "2026-11-06T17:18:14.390",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_exthdr: fix register tracking for F_PRESENT flag\n\nnft_exthdr_init() passes user-controlled priv->len to\nnft_parse_register_store(), which marks that many bytes in the\nregister bitmap as initialized. However, when NFT_EXTHDR_F_PRESENT\nis set, the eval paths write only 1 byte (nft_reg_store8) or\n4 bytes (*dest = 0 on TCP/DCCP error path). When len > 4,\nregisters beyond the first are never written, retaining\nuninitialized stack data from nft_regs.\n\nBail out if userspace requests too much data when F_PRESENT is set."
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