CVE-2026-68288 net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD
A local attacker can read uninitialized kernel memory via netlink messages due to missing padding initialization in the drop monitor subsystem.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68288?
CVE-2026-68288 is a vulnerability in Linux, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: drop_monitor: fix info leak in NET_DM_ATTR_PAYLOAD
net_dm_packet_report_fill() and net_dm_hw_packet_report_fill() open code the NET_DM_ATTR_PAYLOAD attribute to avoid zeroing the packet payload before overwriting it with skb_copy_bits().
skb_put() reserves nla_total_size(payload_len), i.e. the header plus the NLA_ALIGN() padding, but only payload_len bytes are copied in. When payload_len is not a multiple of 4 the 1-3 padding bytes are never initialized and are leaked to user space inside the netlink message.
KMSAN confirms the leak for the software path when the packet payload length is not 4-byte aligned:
BUG: KMSAN: kernel-infoleak in _copy_to_iter _copy_to_iter __skb_datagram_iter skb_copy_datagram_iter netlink_recvmsg sock_recvmsg __sys_recvfrom Uninit was created at: kmem_cache_alloc_node_noprof __alloc_skb net_dm_packet_work Bytes 173-175 of 176 are uninitialized
Use __nla_reserve(), which sets up the attribute header and zeroes the padding, instead of open coding the attribute construction.
Which versions are affected by CVE-2026-68288?
How do I fix CVE-2026-68288?
Apply the vendor's patch.
Is CVE-2026-68288 being exploited?
There is no known exploitation of CVE-2026-68288 in the wild and no public exploit code.
Sources
Also known as AZL-94899, BELL-CVE-2026-68288, DEBIAN-CVE-2026-68288, GHSA-gmx4-77qw-24m9, UBUNTU-CVE-2026-68288.