CVE-2025-38574

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> pptp: ensure minimal skb length in pptp_xmit()<br /> <br /> Commit aabc6596ffb3 ("net: ppp: Add bound checking for skb data<br /> on ppp_sync_txmung") fixed ppp_sync_txmunge()<br /> <br /> We need a similar fix in pptp_xmit(), otherwise we might<br /> read uninit data as reported by syzbot.<br /> <br /> BUG: KMSAN: uninit-value in pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193<br /> pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193<br /> ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2290 [inline]<br /> ppp_input+0x1d6/0xe60 drivers/net/ppp/ppp_generic.c:2314<br /> pppoe_rcv_core+0x1e8/0x760 drivers/net/ppp/pppoe.c:379<br /> sk_backlog_rcv+0x142/0x420 include/net/sock.h:1148<br /> __release_sock+0x1d3/0x330 net/core/sock.c:3213<br /> release_sock+0x6b/0x270 net/core/sock.c:3767<br /> pppoe_sendmsg+0x15d/0xcb0 drivers/net/ppp/pppoe.c:904<br /> sock_sendmsg_nosec net/socket.c:712 [inline]<br /> __sock_sendmsg+0x330/0x3d0 net/socket.c:727<br /> ____sys_sendmsg+0x893/0xd80 net/socket.c:2566<br /> ___sys_sendmsg+0x271/0x3b0 net/socket.c:2620<br /> __sys_sendmmsg+0x2d9/0x7c0 net/socket.c:2709