CVE-2026-31664

Summary

In the Linux kernel, the following vulnerability has been resolved:

xfrm: clear trailing padding in build_polexpire()

build_expire() clears the trailing padding bytes of struct xfrm_user_expire after setting the hard field via memset_after(), but the analogous function build_polexpire() does not do this for struct xfrm_user_polexpire.

The padding bytes after the __u8 hard field are left uninitialized from the heap allocation, and are then sent to userspace via netlink multicast to XFRMNLGRP_EXPIRE listeners, leaking kernel heap memory contents.

Add the missing memset_after() call, matching build_expire().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a5127501c8d30b5728791b1e340284ca5c9cc4bdaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e6f4ffe8596947a595c9544e73a73adcb0568b88affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < ac6985903db047eaff54db929e4bf6b06782788eaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c221ed63a2769a0af8bd849dfe25740048f34ef4affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < eda30846ea54f8ed218468e5480c8305ca645e37affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b1dfd6b27df35ef4f87825aa5f607378d23ff0f2affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < e1af65c669ebb1666c54576614c01a7f9ffcfff6affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 71a98248c63c535eaa4d4c22f099b68d902006d0affected
LinuxLinux2.6.12affected
LinuxLinux0 < 2.6.12unaffected
LinuxLinux5.10.258 <= 5.10.*unaffected
LinuxLinux5.15.209 <= 5.15.*unaffected
LinuxLinux6.1.169 <= 6.1.*unaffected
LinuxLinux6.6.135 <= 6.6.*unaffected
LinuxLinux6.12.82 <= 6.12.*unaffected
LinuxLinux6.18.23 <= 6.18.*unaffected
LinuxLinux6.19.13 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References