CVE-2025-40278: net: sched: act_ife: initialize struct tc_ife to fix KMSAN kernel-infoleak

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-06 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: net: sched: act_ife: initialize struct tc_ife to fix KMSAN kernel-infoleak Fix a KMSAN kernel-infoleak detected by the syzbot . [net?] KMSAN: kernel-infoleak in __skb_datagram_iter In tcf_ife_dump(), the variable 'opt' was partially initialized using a designatied initializer. While the padding bytes are reamined uninitialized. nla_put() copies the entire structure into a netlink message, these uninitialized bytes leaked to userspace. Initialize the structure with memset before assigning its fields to ensure all members and padding are cleared prior to beign copied. This change silences the KMSAN report and prevents potential information leaks from the kernel memory. This fix has been tested and validated by syzbot. This patch closes the bug reported at the following syzkaller link and ensures no infoleak.

Affected products

Linux kernel: 4.6 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

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