Qemu: NULL Pointer Dereference
CVE-2022-36648 is a critical-severity NULL pointer dereference vulnerability in Qemu, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Qemu versions: 7.0.0 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.73% chance of exploitation within 30 days, higher than 78% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Qemu you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
Official description
The hardware emulation in the of_dpa_cmd_add_l2_flood of rocker device model in QEMU, as used in 7.0.0 and earlier, allows remote attackers to crash the host qemu and potentially execute code on the host via execute a malformed program in the guest OS. Note: This has been disputed by multiple third parties as not a valid vulnerability due to the rocker device not falling within the virtualization use case.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL.
How developers prevent this class of flaw
- For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
- Select a programming language that is not susceptible to these issues.
- Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Other vulnerabilities in Qemu
- 7.8 High severity
- 8.8 High severity
- 7.1 High severity
- 7.0 High severity
- 8.2 High severity
- 7.8 High severity
Recent NULL Pointer Dereference vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
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