{"id":"CVE-2026-53250","revision":"d43f683937d6467481e925a097ffd036","records":[{"revision":"d43f683937d6467481e925a097ffd036","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-53250","aliases":[],"title":"xsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxsk: cache csum_start/csum_offset to fix TOCTOU in xsk_skb_metadata()\n\nThe TX metadata area resides in the UMEM buffer which is memory-mapped\nand concurrently writable by userspace. In xsk_skb_metadata(),\ncsum_start and csum_offset are read from shared memory for bounds\nvalidation, then read again for skb assignment. A malicious userspace\napplication can race to overwrite these values between the two reads,\nbypassing the bounds check and causing out-of-bounds memory access\nduring checksum computation in the transmit path.\n\nFix this by reading csum_start and csum_offset into local variables\nonce, then using the local copies for both validation and assignment.\n\nNote that other metadata fields (flags, launch_time) and the cached\ncsum fields may be mutually inconsistent due to concurrent userspace\nwrites, but this is benign: the only security-critical invariant is\nthat each field's validated value is the same one used, which local\ncaching guarantees.","state":0,"publishedAt":"2026-06-25T08:39:42.63+00:00","modifiedAt":"2026-10-19T19:57:31.573+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/xdp/xsk.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"48eb03dd26304c24f03bdbb9382e89c8564e71df\",\n                            \"lessThan\": \"eb778aed8a9b2381668fcb1247ae4fa011224768\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"48eb03dd26304c24f03bdbb9382e89c8564e71df\",\n                            \"lessThan\": \"0dfe05b938435892875e07771170051346412df9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"48eb03dd26304c24f03bdbb9382e89c8564e71df\",\n                            \"lessThan\": \"bfdfd2706d5fb2cd496a1506e680daf979309c8b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"48eb03dd26304c24f03bdbb9382e89c8564e71df\",\n                            \"lessThan\": \"22ba97ea9cc1f63a0d0244fae38057ed452b6ac7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/xdp/xsk.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.8\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.8\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.110\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.36\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.0.13\",\n                            \"lessThanOrEqual\": \"7.0.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/eb778aed8a9b2381668fcb1247ae4fa011224768","https://git.kernel.org/stable/c/0dfe05b938435892875e07771170051346412df9","https://git.kernel.org/stable/c/bfdfd2706d5fb2cd496a1506e680daf979309c8b","https://git.kernel.org/stable/c/22ba97ea9cc1f63a0d0244fae38057ed452b6ac7"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-53250","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-53250","identifiers":["CVE-2026-53250"]},"retained":false,"historicalAffected":[]}],"coverage":[]}