CVE-2025-38465

En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netlink: Se corrigen los wraparounds de sk->sk_rmem_alloc. Netlink presenta este patrón en algunos lugares if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) atomic_add(skb->truesize, &sk->sk_rmem_alloc); , que presenta el mismo problema corregido por el commit 5a465a0da13e ("udp: Se corrigen múltiples wraparounds de sk->sk_rmem_alloc."). Por ejemplo, si establecemos INT_MAX en SO_RCVBUFFORCE, la condición siempre es falsa, ya que los dos operandos son de tipo int. En ese caso, un solo socket puede consumir tantos skb como sea posible hasta que se produzca un OOM, y podemos observar múltiples wraparounds de sk->sk_rmem_alloc. Para solucionarlo, usemos atomic_add_return() y comparemos las dos variables como enteros sin signo. Antes: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Dirección local: Puerto Dirección del par: Puerto -1668710080 0 rtnl:nl_wraparound/293 * Después: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Dirección local: Puerto Dirección del par: Puerto 2147483072 0 rtnl:nl_wraparound/290 * ^ `--- INT_MAX - 576

In the Linux kernel, the following vulnerability has been resolved: netlink: Fix wraparounds of sk->sk_rmem_alloc. Netlink has this pattern in some places if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) atomic_add(skb->truesize, &sk->sk_rmem_alloc); , which has the same problem fixed by commit 5a465a0da13e ("udp: Fix multiple wraparounds of sk->sk_rmem_alloc."). For example, if we set INT_MAX to SO_RCVBUFFORCE, the condition is always false as the two operands are of int. Then, a single socket can eat as many skb as possible until OOM happens, and we can see multiple wraparounds of sk->sk_rmem_alloc. Let's fix it by using atomic_add_return() and comparing the two variables as unsigned int. Before: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port -1668710080 0 rtnl:nl_wraparound/293 * After: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port 2147483072 0 rtnl:nl_wraparound/290 * ^ `--- INT_MAX - 576

It was discovered that improper initialization of CPU cache memory could allow a local attacker with hypervisor access to overwrite SEV-SNP guest memory resulting in loss of data integrity. Jean-Claude Graf, Sandro Rüegge, Ali Hajiabadi, and Kaveh Razavi discovered that the Linux kernel contained insufficient branch predictor isolation between a guest and a userspace hypervisor for certain processors. This flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this to expose sensitive information from the host OS.