{"id":"CVE-2026-31664","title":"xfrm: clear trailing padding in build_polexpire()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: clear trailing padding in build_polexpire()\n\nbuild_expire() clears the trailing padding bytes of struct\nxfrm_user_expire after setting the hard field via memset_a…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a5127501c8d30b5728791b1e340284ca5c9cc4bd","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e6f4ffe8596947a595c9544e73a73adcb0568b88","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ac6985903db047eaff54db929e4bf6b06782788e","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c221ed63a2769a0af8bd849dfe25740048f34ef4","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < eda30846ea54f8ed218468e5480c8305ca645e37","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b1dfd6b27df35ef4f87825aa5f607378d23ff0f2","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e1af65c669ebb1666c54576614c01a7f9ffcfff6","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 71a98248c63c535eaa4d4c22f099b68d902006d0","Linux 2.6.12"],"published":"2026-04-24","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:47:55.898Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31664","references":[{"url":"https://git.kernel.org/stable/c/a5127501c8d30b5728791b1e340284ca5c9cc4bd"},{"url":"https://git.kernel.org/stable/c/e6f4ffe8596947a595c9544e73a73adcb0568b88"},{"url":"https://git.kernel.org/stable/c/ac6985903db047eaff54db929e4bf6b06782788e"},{"url":"https://git.kernel.org/stable/c/c221ed63a2769a0af8bd849dfe25740048f34ef4"},{"url":"https://git.kernel.org/stable/c/eda30846ea54f8ed218468e5480c8305ca645e37"},{"url":"https://git.kernel.org/stable/c/b1dfd6b27df35ef4f87825aa5f607378d23ff0f2"},{"url":"https://git.kernel.org/stable/c/e1af65c669ebb1666c54576614c01a7f9ffcfff6"},{"url":"https://git.kernel.org/stable/c/71a98248c63c535eaa4d4c22f099b68d902006d0"}],"tags":["cve.org"],"epss":0.0012,"epssPercentile":0.02077,"ingestedAt":"2026-09-08T15:33:26.989Z","slug":"CVE-2026-31664","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: clear trailing padding in build_polexpire()\n\nbuild_expire() clears the trailing padding bytes of struct\nxfrm_user_expire after setting the hard field via memset_after(),\nbut the analogous function build_polexpire() does not do this for\nstruct xfrm_user_polexpire.\n\nThe padding bytes after the __u8 hard field are left\nuninitialized from the heap allocation, and are then sent to\nuserspace via netlink multicast to XFRMNLGRP_EXPIRE listeners,\nleaking kernel heap memory contents.\n\nAdd the missing memset_after() call, matching build_expire().\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a5127501c8d30b5728791b1e340284ca5c9cc4bd`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e6f4ffe8596947a595c9544e73a73adcb0568b88`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ac6985903db047eaff54db929e4bf6b06782788e`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c221ed63a2769a0af8bd849dfe25740048f34ef4`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < eda30846ea54f8ed218468e5480c8305ca645e37`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b1dfd6b27df35ef4f87825aa5f607378d23ff0f2`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e1af65c669ebb1666c54576614c01a7f9ffcfff6`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 71a98248c63c535eaa4d4c22f099b68d902006d0`\n- `Linux 2.6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}