# 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.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-94899, BELL-CVE-2026-68288, DEBIAN-CVE-2026-68288, GHSA-gmx4-77qw-24m9, UBUNTU-CVE-2026-68288

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68288 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-68288 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68288/ (Markdown: https://insights.sbomify.com/CVE-2026-68288/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68288
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68288
- OSV: https://osv.dev/vulnerability/CVE-2026-68288

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68288/
Summaries are generated and may contain mistakes; the official description above is the record.