CVE-2026-31675

Summary

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

net/sched: sch_netem: fix out-of-bounds access in packet corruption

In netem_enqueue(), the packet corruption logic uses get_random_u32_below(skb_headlen(skb)) to select an index for modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.

Passing 0 to get_random_u32_below() takes the variable-ceil slow path which returns an unconstrained 32-bit random integer. Using this unconstrained value as an offset into skb->data results in an out-of-bounds memory access.

Fix this by verifying skb_headlen(skb) is non-zero before attempting to corrupt the linear data area. Fully non-linear packets will silently bypass the corruption logic.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxc865e5d99e25a171e8262fc0f7ba608568633c64 < a14b56863348686dd0387eea8ce66b85cf455908affected
LinuxLinuxc865e5d99e25a171e8262fc0f7ba608568633c64 < 13a66ca1e235d4bcd53d12d4c68490cad7f8e46faffected
LinuxLinuxc865e5d99e25a171e8262fc0f7ba608568633c64 < 3a2999704ac36cfb4041fed3652d26a3373e8d12affected
LinuxLinuxc865e5d99e25a171e8262fc0f7ba608568633c64 < 4fd258e281fa8bc15e9ce2c7691941537e9258adaffected
LinuxLinuxc865e5d99e25a171e8262fc0f7ba608568633c64 < d64cb81dcbd54927515a7f65e5e24affdc73c14baffected
LinuxLinux2.6.16affected
LinuxLinux0 < 2.6.16unaffected
LinuxLinux6.6.134 <= 6.6.*unaffected
LinuxLinux6.12.81 <= 6.12.*unaffected
LinuxLinux6.18.22 <= 6.18.*unaffected
LinuxLinux6.19.12 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References