xfrm: clear trailing padding in build_polexpire()

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().

Timeline

1. Apr 24, 2026, 2:45 PM UTCCVE published
2. Oct 15, 2026, 1:17 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in a5127501c8d30b5728791b1e340284ca5c9cc4bd; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in e6f4ffe8596947a595c9544e73a73adcb0568b88; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in ac6985903db047eaff54db929e4bf6b06782788e; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in c221ed63a2769a0af8bd849dfe25740048f34ef4; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in eda30846ea54f8ed218468e5480c8305ca645e37; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in b1dfd6b27df35ef4f87825aa5f607378d23ff0f2; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in e1af65c669ebb1666c54576614c01a7f9ffcfff6; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 71a98248c63c535eaa4d4c22f099b68d902006d0

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.169; From 6.2.0 · fixed in 6.6.135; From 6.7.0 · fixed in 6.12.82; From 6.13.0 · fixed in 6.18.23; From 6.19.0 · fixed in 6.19.13

References 8