VYPR
← All advisories
High severity7.1NVD Advisory· Published Oct 21, 2024· Updated May 12, 2026

CVE-2024-50033

CVE-2024-50033

Description

In the Linux kernel, the following vulnerability has been resolved:

slip: make slhc_remember() more robust against malicious packets

syzbot found that slhc_remember() was missing checks against malicious packets [1].

slhc_remember() only checked the size of the packet was at least 20, which is not good enough.

We need to make sure the packet includes the IPv4 and TCP header that are supposed to be carried.

Add iph and th pointers to make the code more readable.

[1]

BUG: KMSAN: uninit-value in slhc_remember+0x2e8/0x7b0 drivers/net/slip/slhc.c:666 slhc_remember+0x2e8/0x7b0 drivers/net/slip/slhc.c:666 ppp_receive_nonmp_frame+0xe45/0x35e0 drivers/net/ppp/ppp_generic.c:2455 ppp_receive_frame drivers/net/ppp/ppp_generic.c:2372 [inline] ppp_do_recv+0x65f/0x40d0 drivers/net/ppp/ppp_generic.c:2212 ppp_input+0x7dc/0xe60 drivers/net/ppp/ppp_generic.c:2327 pppoe_rcv_core+0x1d3/0x720 drivers/net/ppp/pppoe.c:379 sk_backlog_rcv+0x13b/0x420 include/net/sock.h:1113 __release_sock+0x1da/0x330 net/core/sock.c:3072 release_sock+0x6b/0x250 net/core/sock.c:3626 pppoe_sendmsg+0x2b8/0xb90 drivers/net/ppp/pppoe.c:903 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:744 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742 __do_sys_sendmmsg net/socket.c:2771 [inline] __se_sys_sendmmsg net/socket.c:2768 [inline] __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at: slab_post_alloc_hook mm/slub.c:4091 [inline] slab_alloc_node mm/slub.c:4134 [inline] kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4186 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1322 [inline] sock_wmalloc+0xfe/0x1a0 net/core/sock.c:2732 pppoe_sendmsg+0x3a7/0xb90 drivers/net/ppp/pppoe.c:867 sock_sendmsg_nosec net/socket.c:729 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:744 ____sys_sendmsg+0x903/0xb60 net/socket.c:2602 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2656 __sys_sendmmsg+0x3c1/0x960 net/socket.c:2742 __do_sys_sendmmsg net/socket.c:2771 [inline] __se_sys_sendmmsg net/socket.c:2768 [inline] __x64_sys_sendmmsg+0xbc/0x120 net/socket.c:2768 x64_sys_call+0xb6e/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:308 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5460 Comm: syz.2.33 Not tainted 6.12.0-rc2-syzkaller-00006-g87d6aab2389e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

slip driver's slhc_remember() missing packet header validation allows uninit memory access.

A vulnerability in the Linux kernel's slip driver (drivers/net/slip/slhc.c) was discovered in the slhc_remember() function. The function only checked that the packet size was at least 20 bytes, but did not verify the presence of proper IPv4 and TCP headers. This insufficient validation could be exploited by a malicious packet to access uninitialized memory, as demonstrated by syzbot.

An attacker can send a specially crafted packet over a PPP link that uses slip compression (e.g., PPPoE). No special privileges are required if the attacker can deliver a packet to the target interface. The attack vector is remote network, but local access may also be possible. The vulnerability was found through syzkaller fuzzing, indicating a potentially easy trigger.

Impact: The uninitialized memory access can lead to a kernel information disclosure or a system crash (denial of service). The CVSS v3 base score of 7.1 reflects the high severity, with confidentiality and availability impacts. The vulnerability affects all versions of the Linux kernel before the patch.

Mitigation: The fix adds explicit checks for IPv4 and TCP header pointers, ensuring the packet contains valid headers before processing. The patch has been applied to the Linux kernel stable tree. Users should update to a kernel version containing the commit that addresses CVE-2024-50033.

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

113

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

11

News mentions

0

No linked articles in our index yet.