CVE-2025-38574

pptp: ensure minimal skb length in pptp_xmit()

State: Published
Severity: 8.6 High
Published: Aug 19, 2025
Updated: Oct 15, 2026
Reserved: Apr 16, 2025

Description

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

Scores

CVSS	Score	Vector	Source
3.1	8.6 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 97b8c5d322c5c0038cac4bc56fdbe237d0be426fAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 26672f1679b143aa34fca0b6046b7fd0c184770dAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5de7513f38f3c19c0610294ee478242bea356f8cAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 504cc4ab91073d2ac7404ad146139f86ecee7193Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5005d24377378a20e5c0e53052fc4ebdcdcbc611Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before ea99b88b1999ebcb24d5d3a6b7910030f40d3bbaAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b7dcda76fd0615c0599c89f36873a6cd48e02dbbAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 1a04db0fd75cb6034fc27a56b67b3b8b9022a98cAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before de9c4861fb42f0cd72da844c3c34f692d5895b7bAffected
LinuxLinux	2.6.12Affected before 2.6.12Not affected 5.4.297 through 5.4.Not affected 5.10.241 through 5.10.Not affected 5.15.190 through 5.15.Not affected 6.1.148 through 6.1.Not affected 6.6.102 through 6.6.Not affected 6.12.42 through 6.12.Not affected 6.15.10 through 6.15.Not affected 6.16.1 through 6.16.Not affected 6.17 and laterNot affected

Product

Versions

LinuxLinux

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 97b8c5d322c5c0038cac4bc56fdbe237d0be426fAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 26672f1679b143aa34fca0b6046b7fd0c184770dAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5de7513f38f3c19c0610294ee478242bea356f8cAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 504cc4ab91073d2ac7404ad146139f86ecee7193Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5005d24377378a20e5c0e53052fc4ebdcdcbc611Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before ea99b88b1999ebcb24d5d3a6b7910030f40d3bbaAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before b7dcda76fd0615c0599c89f36873a6cd48e02dbbAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 1a04db0fd75cb6034fc27a56b67b3b8b9022a98cAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before de9c4861fb42f0cd72da844c3c34f692d5895b7bAffected

LinuxLinux

2.6.12Affected
before 2.6.12Not affected
5.4.297 through 5.4.*Not affected
5.10.241 through 5.10.*Not affected
5.15.190 through 5.15.*Not affected
6.1.148 through 6.1.*Not affected
6.6.102 through 6.6.*Not affected
6.12.42 through 6.12.*Not affected
6.15.10 through 6.15.*Not affected
6.16.1 through 6.16.*Not affected
6.17 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.