CVE-2026-74290

Summary

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

net/sched: cls_flow: Dont expose folded kernel pointers

The flow classifier falls back to addr_fold() for fields that are missing from packet headers. In map mode, userspace controls mask, xor, rshift, addend and divisor, and can observe the resulting classid through class statistics. This allows a tc classifier in a user/network namespace to recover the 32-bit folded value of skb->sk, skb_dst() or skb_nfct().

Align with standard kernel practices for pointer hashing and replace the XOR folding with a keyed siphash (which is cryptographically secure)

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe5dfb815181fcb186d6080ac3a091eadff2d98fe < 19f2ecf8ea564562c7e7a919cf38068dd9aa1c96affected
LinuxLinuxe5dfb815181fcb186d6080ac3a091eadff2d98fe < 3d054001860270748405a3f9270c5fa0bf7ffc19affected
LinuxLinuxe5dfb815181fcb186d6080ac3a091eadff2d98fe < fb31fbe51c233f3bf47021121f63d2e42cac2d08affected
LinuxLinuxe5dfb815181fcb186d6080ac3a091eadff2d98fe < 0a8b5b74f0e6b6b9ce453bcfa4baa502c4c7577aaffected
LinuxLinuxe5dfb815181fcb186d6080ac3a091eadff2d98fe < 6151159618198675e01c391676e579738286c135affected
LinuxLinuxe5dfb815181fcb186d6080ac3a091eadff2d98fe < f294fc71c4a0fa4964f6428a1b4e7929c1d83125affected
LinuxLinux2.6.25affected
LinuxLinux0 < 2.6.25unaffected
LinuxLinux6.1.178 <= 6.1.*unaffected
LinuxLinux6.6.145 <= 6.6.*unaffected
LinuxLinux6.12.97 <= 6.12.*unaffected
LinuxLinux6.18.40 <= 6.18.*unaffected
LinuxLinux7.1.5 <= 7.1.*unaffected
LinuxLinux7.2 <= *unaffected

Weaknesses

References