# CVE-2026-68287: drop_monitor: fix size calculations for 64-bit attributes

> An integer overflow in Linux kernel drop_monitor size calculations can cause a kernel panic, leading to denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-94968, BELL-CVE-2026-68287, DEBIAN-CVE-2026-68287, GHSA-mc29-r954-2m26, UBUNTU-CVE-2026-68287

## What is CVE-2026-68287?

CVE-2026-68287 is a high-severity vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

drop_monitor: fix size calculations for 64-bit attributes

net_dm_packet_report_fill() and net_dm_hw_packet_report_fill() use
nla_put_u64_64bit() to append 64-bit attributes (NET_DM_ATTR_PC and
NET_DM_ATTR_TIMESTAMP).

On 32-bit architectures without CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS,
nla_put_u64_64bit() may append a 4-byte NET_DM_ATTR_PAD attribute for
64-bit alignment.

However, net_dm_packet_report_size() and net_dm_hw_packet_report_size()
used nla_total_size(sizeof(u64)) instead of nla_total_size_64bit(sizeof(u64)),
budgeting 12 bytes instead of up to 16 bytes.

This under-estimation of SKB size can lead to an skb_over_panic() when
__nla_reserve() or skb_put() is subsequently called.

Fix this by using nla_total_size_64bit(sizeof(u64)) in both size calculations.

Weakness: CWE-131 (Incorrect Calculation of Buffer Size)

## Which versions are affected by CVE-2026-68287?


## How do I fix CVE-2026-68287?

Apply the vendor's patch.

## Is CVE-2026-68287 being exploited?

There is no known exploitation of CVE-2026-68287 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68287 and fix it if it is affected.

What it is: CVE-2026-68287 is a high-severity vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68287 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-2026-68287/ (Markdown: https://insights.sbomify.com/CVE-2026-68287/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68287
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68287
- OSV: https://osv.dev/vulnerability/CVE-2026-68287

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68287/
Summaries are generated and may contain mistakes; the official description above is the record.