Linux Kernel up to 5.17.2 denial of service

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 5.17.2. This impacts an unknown function. Executing a manipulation can lead to denial of service. This vulnerability appears as CVE-2022-49124. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 5.17.2 and classified as critical. This vulnerability affects an unknown part. The manipulation with an unknown input leads to a denial of service vulnerability. The CWE definition for the vulnerability is CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: x86/mce: Work around an erratum on fast string copy instructions A rare kernel panic scenario can happen when the following conditions are met due to an erratum on fast string copy instructions: 1) An uncorrected error. 2) That error must be in first cache line of a page. 3) Kernel must execute page_copy from the page immediately before that page. The fast string copy instructions ("REP; MOVS*") could consume an uncorrectable memory error in the cache line _right after_ the desired region to copy and raise an MCE. Bit 0 of MSR_IA32_MISC_ENABLE can be cleared to disable fast string copy and will avoid such spurious machine checks. However, that is less preferable due to the permanent performance impact. Considering memory poison is rare, it's desirable to keep fast string copy enabled until an MCE is seen. Intel has confirmed the following: 1. The CPU erratum of fast string copy only applies to Skylake, Cascade Lake and Cooper Lake generations. Directly return from the MCE handler: 2. Will result in complete execution of the "REP; MOVS*" with no data loss or corruption. 3. Will not result in another MCE firing on the next poisoned cache line due to "REP; MOVS*". 4. Will resume execution from a correct point in code. 5. Will result in the same instruction that triggered the MCE firing a second MCE immediately for any other software recoverable data fetch errors. 6. Is not safe without disabling the fast string copy, as the next fast string copy of the same buffer on the same CPU would result in a PANIC MCE. This should mitigate the erratum completely with the only caveat that the fast string copy is disabled on the affected hyper thread thus performance degradation. This is still better than the OS crashing on MCEs raised on an irrelevant process due to "REP; MOVS*' accesses in a kernel context, e.g., copy_page. Injected errors on 1st cache line of 8 anonymous pages of process 'proc1' and observed MCE consumption from 'proc2' with no panic (directly returned). Without the fix, the host panicked within a few minutes on a random 'proc2' process due to kernel access from copy_page. [ bp: Fix comment style + touch ups, zap an unlikely(), improve the quirk function's readability. ]

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2022-49124 since 02/26/2025. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 232643 (SUSE SLES12 Security Update : kernel (SUSE-SU-2025:0834-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.17.3 eliminates this vulnerability. Applying the patch ba37c73be3d5632f6fb9fa20b250ce45560ca85d/8ca97812c3c830573f965a07bbd84223e8c5f5bd is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (232643) and EUVD (EUVD-2022-55091). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.17.0
• 5.17.1
• 5.17.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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