Linux Kernel: Zero Padding Leak in xfrm_user Report Structure
CVE-2026-31671 Published on April 24, 2026
xfrm_user: fix info leak in build_report()
In the Linux kernel, the following vulnerability has been resolved:
xfrm_user: fix info leak in build_report()
struct xfrm_user_report is a __u8 proto field followed by a struct
xfrm_selector which means there is three "empty" bytes of padding, but
the padding is never zeroed before copying to userspace. Fix that up by
zeroing the structure before setting individual member variables.
Products Associated with CVE-2026-31671
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Affected Versions
Linux:- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below d27c02eec529f78055a46a5c9e6c62684382b2d8 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 716c546e88cfe49d841658240e10cb57bc50a2cc is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 0616314b3b34f24cbb91da8c6bd8bcdc4c8592f9 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below e0c8542c3d097ed4205ded51868195d5d6ddac62 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below ff5ee507302303b15859753c3e0d67d38fd12c88 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 6c55714c931051cd7f4839c19ce0867179fd22fe is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below 0a30dceb0e1f0c480d2482e6d7cebf8aebb6eb72 is affected.
- Version 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and below d10119968d0e1f2b669604baf2a8b5fdb72fa6b4 is affected.
- Version 5.10.253, <= 5.10.* is unaffected.
- Version 5.15.203, <= 5.15.* is unaffected.
- Version 6.1.169, <= 6.1.* is unaffected.
- Version 6.6.135, <= 6.6.* is unaffected.
- Version 6.12.82, <= 6.12.* is unaffected.
- Version 6.18.23, <= 6.18.* is unaffected.
- Version 6.19.13, <= 6.19.* is unaffected.
- Version 7.0, <= * is unaffected.