# CVE-2026-64548: bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()

> An integer overflow in the Linux kernel's BPF sockmap allows attackers to trigger out-of-bounds memory writes, potentially leading to code execution or system crashes.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-94053, BELL-CVE-2026-64548, DEBIAN-CVE-2026-64548, GHSA-v3w7-wgcw-wjf2, ROOT-OS-DEBIAN-12-CVE-2026-64548, UBUNTU-CVE-2026-64548

## What is CVE-2026-64548?

CVE-2026-64548 is a high-severity vulnerability in Linux, published on 27 Jul 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:

bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()

When the scatterlist ring is full or nearly full, bpf_msg_push_data()
enters a copy fallback path and computes copy + len for the page
allocation size. Since len comes from BPF with arg3_type = ARG_ANYTHING
and both are u32, a crafted len can wrap the sum to a small value,
causing an undersized allocation followed by an out-of-bounds memcpy.

 BUG: unable to handle page fault for address: ffffed104089a402
 Oops: Oops: 0000 [#1] SMP KASAN NOPTI
 Call Trace:
  __asan_memcpy (mm/kasan/shadow.c:105)
  bpf_msg_push_data (net/core/filter.c:2852 net/core/filter.c:2788)
  bpf_prog_9ed8b5711920a7d7+0x2e/0x36
  sk_psock_msg_verdict (net/core/skmsg.c:934)
  tcp_bpf_sendmsg (net/ipv4/tcp_bpf.c:421 net/ipv4/tcp_bpf.c:584)
  __sys_sendto (net/socket.c:2206)
  do_syscall_64 (arch/x86/entry/syscall_64.c:94)
  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)

Add an overflow check before the allocation.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-64548?


## How do I fix CVE-2026-64548?

Apply the vendor's patch.

## Is CVE-2026-64548 being exploited?

There is no known exploitation of CVE-2026-64548 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64548 and fix it if it is affected.

What it is: CVE-2026-64548 is a high-severity vulnerability in Linux, published on 27 Jul 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-2026-64548 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-2026-64548/ (Markdown: https://insights.sbomify.com/CVE-2026-64548/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64548
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64548
- OSV: https://osv.dev/vulnerability/CVE-2026-64548

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64548/
Summaries are generated and may contain mistakes; the official description above is the record.