CVE-2026-31675

Description

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.

References

• https://git.kernel.org/stable/c/13a66ca1e235d4bcd53d12d4c68490cad7f8e46f
• https://git.kernel.org/stable/c/3a2999704ac36cfb4041fed3652d26a3373e8d12
• https://git.kernel.org/stable/c/4fd258e281fa8bc15e9ce2c7691941537e9258ad
• https://git.kernel.org/stable/c/a14b56863348686dd0387eea8ce66b85cf455908
• https://git.kernel.org/stable/c/d64cb81dcbd54927515a7f65e5e24affdc73c14b