CVE-2022-43945: Buffer Overflow
A buffer overflow flaw was found in the Linux kernel nfsd (network file system) subsystem. The way a user sends RPC over TCP with excess data added at the end of the message could allow a remote user to starve the resources, causing a denial of service.
Other sources
A flaw in the Linux Kernel nfsd (network file system) found. Remote user can send RPC over TCP with garbage data added at the end of the message. It can lead to NFSD send/receive buffer overflow on the server side, but without actual out of bounds memory access, so only deny of service possible.
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f90497a16e434c2211c66e3de8e77b17868382b8
— Red Hat
The Linux kernel NFSD implementation prior to versions 5.19.17 and 6.0.2 are vulnerable to buffer overflow. NFSD tracks the number of pages held by each NFSD thread by combining the receive and send buffers of a remote procedure call (RPC) into a single array of pages. A client can force the send buffer to shrink by sending an RPC message over TCP with garbage data added at the end of the message. The RPC message with garbage data is still correctly formed according to the specification and is passed forward to handlers. Vulnerable code in NFSD is not expecting the oversized request and writes beyond the allocated buffer space. CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:4.18.0-425.13.1.rt7.223.el8_7 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-425.13.1.el8_7 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:5.14.0-162.12.1.el9_1 - Upgrade
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redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:5.14.0-162.12.1.rt21.175.el9_1 - Upgrade
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redhat/kernelto a version that resolves this vulnerability.Fixed in 0:5.14.0-70.36.1.el9_0 - Upgrade
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redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:5.14.0-70.36.1.rt21.108.el9_0 - Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1Fixed in 6.12.27-1 - Upgrade
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linux kernel nfsdto a version that resolves this vulnerability.Fixed in 5.19.17 - Upgrade
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linux kernel nfsdto a version that resolves this vulnerability.Fixed in 6.0.2
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2022-43945?
CVE-2022-43945 has a severity rating that suggests it could lead to a denial of service due to a buffer overflow in the Linux kernel's nfsd subsystem.
How do I fix CVE-2022-43945?
To mitigate CVE-2022-43945, upgrade to patched kernel versions, specifically kernel-rt versions 0:4.18.0-425.13.1.rt7.223.el8_7, or other specified updates.
Which Linux kernel versions are affected by CVE-2022-43945?
CVE-2022-43945 affects various versions of the Linux kernel including those before versions 0:4.18.0-425.13.1.el8_7 and 0:5.14.0-162.12.1.el9_1.
What are the potential impacts of CVE-2022-43945?
The potential impact of CVE-2022-43945 is a denial of service, which could starve resources and disrupt system functionality for users.
Is there a workaround for CVE-2022-43945?
While the best course of action is to apply the relevant updates, temporarily limiting network access to the nfsd service can help reduce exposure until a fix is implemented.