CVE-2024-26596

Advisory lineage Upstream: 0 Downstream: 11
Modified
Published: 23 Feb 2024, 14:46
Last modified:12 May 2026, 11:49

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
0.01% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

23 Feb 2024, 14:46
Published
Vulnerability first disclosed
12 May 2026, 11:49
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: net: dsa: fix netdev_priv() dereference before check on non-DSA netdevice events After the blamed commit, we started doing this dereference for every NETDEV_CHANGEUPPER and NETDEV_PRECHANGEUPPER event in the system. static inline struct dsa_port *dsa_user_to_port(const struct net_device *dev) { struct dsa_user_priv *p = netdev_priv(dev); return p->dp; } Which is obviously bogus, because not all net_devices have a netdev_priv() of type struct dsa_user_priv. But struct dsa_user_priv is fairly small, and p->dp means dereferencing 8 bytes starting with offset 16. Most drivers allocate that much private memory anyway, making our access not fault, and we discard the bogus data quickly afterwards, so this wasn't caught. But the dummy interface is somewhat special in that it calls alloc_netdev() with a priv size of 0. So every netdev_priv() dereference is invalid, and we get this when we emit a NETDEV_PRECHANGEUPPER event with a VLAN as its new upper: $ ip link add dummy1 type dummy $ ip link add link dummy1 name dummy1.100 type vlan id 100 [ 43.309174] ================================================================== [ 43.316456] BUG: KASAN: slab-out-of-bounds in dsa_user_prechangeupper+0x30/0xe8 [ 43.323835] Read of size 8 at addr ffff3f86481d2990 by task ip/374 [ 43.330058] [ 43.342436] Call trace: [ 43.366542] dsa_user_prechangeupper+0x30/0xe8 [ 43.371024] dsa_user_netdevice_event+0xb38/0xee8 [ 43.375768] notifier_call_chain+0xa4/0x210 [ 43.379985] raw_notifier_call_chain+0x24/0x38 [ 43.384464] __netdev_upper_dev_link+0x3ec/0x5d8 [ 43.389120] netdev_upper_dev_link+0x70/0xa8 [ 43.393424] register_vlan_dev+0x1bc/0x310 [ 43.397554] vlan_newlink+0x210/0x248 [ 43.401247] rtnl_newlink+0x9fc/0xe30 [ 43.404942] rtnetlink_rcv_msg+0x378/0x580 Avoid the kernel oops by dereferencing after the type check, as customary.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 2%

Affected Systems

  • linux•linux

    ≥ 4c3f80d22b2eca911143ce656fa45c4699ff5bf4, < 9e9953f5e4d6d11a9dad56fdee307bb923302809 | ≥ 4c3f80d22b2eca911143ce656fa45c4699ff5bf4, < 69a1e2d938dbbfcff0e064269adf60ad26dbb102 | ≥ 4c3f80d22b2eca911143ce656fa45c4699ff5bf4, < dbd909c20c11f0d29c0054d41e0d1f668a60e8c8 | ≥ 4c3f80d22b2eca911143ce656fa45c4699ff5bf4, < 844f104790bd69c2e4dbb9ee3eba46fde1fcea7b | 6.1

  • linux•linux_kernel

    ≥ 6.1.0, < 6.7.2

References (6)