High · published August 19, 2025
In the Linux kernel, the following vulnerability has been resolved:
pptp: ensure minimal skb length in pptp_xmit()
Commit aabc6596ffb3 ("net: ppp: Add bound checking for skb data
on ppp_sync_txmung") fixed ppp_sync_txmunge()
We need a similar fix in pptp_xmit(), otherwise we might
read uninit data as reported by syzbot.
BUG: KMSAN: uninit-value in pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193
pptp_xmit+0xc34/0x2720 drivers/net/ppp/pptp.c:193
ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2290 [inline]
ppp_input+0x1d6/0xe60 drivers/net/ppp/ppp_generic.c:2314
pppoe_rcv_core+0x1e8/0x760 drivers/net/ppp/pppoe.c:379
sk_backlog_rcv+0x142/0x420 include/net/sock.h:1148
__release_sock+0x1d3/0x330 net/core/sock.c:3213
release_sock+0x6b/0x270 net/core/sock.c:3767
pppoe_sendmsg+0x15d/0xcb0 drivers/net/ppp/pppoe.c:904
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x330/0x3d0 net/socket.c:727
____sys_sendmsg+0x893/0xd80 net/socket.c:2566
___sys_sendmsg+0x271/0x3b0 net/socket.c:2620
__sys_sendmmsg+0x2d9/0x7c0 net/socket.c:2709
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 2.6.13, < 5.4.297 | 5.4.297 |
| linux/linux_kernel | ≥ 5.5, < 5.10.241 | 5.10.241 |
| linux/linux_kernel | ≥ 5.11, < 5.15.190 | 5.15.190 |
| linux/linux_kernel | ≥ 5.16, < 6.1.148 | 6.1.148 |
| linux/linux_kernel | ≥ 6.2, < 6.6.102 | 6.6.102 |
| linux/linux_kernel | ≥ 6.7, < 6.12.42 | 6.12.42 |
| linux/linux_kernel | ≥ 6.13, < 6.15.10 | 6.15.10 |
| linux/linux_kernel | ≥ 6.16, < 6.16.1 | 6.16.1 |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| linux/linux_kernel | all versions | — |
| debian/debian_linux | all versions | — |