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CVE-2024-26603

MEDIUMCVSS 5.5/10EPSS 0.28%

Last modified

CVE-2024-26603 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Stop relying on userspace for info to fault in xsave buffer Before this change, the expected size of the user space buffer was taken from fx_sw->xstate_size. fx_sw->xstate_size can be changed from user-space, so it is possible construct a sigreturn frame where: * fx_sw->xstate_size is smaller than the size required by valid bits in fx_sw->xfeatures. * user-space unmaps parts of the sigrame fpu buffer so that not all of the buffer required by xrstor is accessible. In this case, xrstor tries to restore and accesses the unmapped area which results in a fault. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Stop relying on userspace for info to fault in xsave buffer Before this change, the expected size of the user space buffer was taken from fx_sw->xstate_size. fx_sw->xstate_size can be changed from user-space, so it is possible construct a sigreturn frame where: * fx_sw->xstate_size is smaller than the size required by valid bits in fx_sw->xfeatures. * user-space unmaps parts of the sigrame fpu buffer so that not all of the buffer required by xrstor is accessible. In this case, xrstor tries to restore and accesses the unmapped area which results in a fault. But fault_in_readable succeeds because buf + fx_sw->xstate_size is within the still mapped area, so it goes back and tries xrstor again. It will spin in this loop forever. Instead, fault in the maximum size which can be touched by XRSTOR (taken from fpstate->user_size). [ dhansen: tweak subject / changelog ]

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.28%

19.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LinuxLinux Kernel>= 5.14.0, < 5.15.150
LinuxLinux Kernel>= 5.16.0, < 6.1.79
LinuxLinux Kernel>= 6.2.0, < 6.6.18
LinuxLinux Kernel>= 6.7.0, < 6.7.6

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2024-26603?
In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Stop relying on userspace for info to fault in xsave buffer Before this change, the expected size of the user space buffer was taken from fx_sw->xstate_size. fx_sw->xstate_size can be changed from user-space, so it is possible construct a sigreturn frame where: * fx_sw->xstate_size is smaller than the size required by valid bits in fx_sw->xfeatures. * user-space unmaps parts of the sigrame fpu buffer so that not all of the buffer required by xrstor is accessible. In this case, xrstor tries to restore and accesses the unmapped area which results in a fault. But fault_in_readable succeeds because buf + fx_sw->xstate_size is within the still mapped area, so it goes back and tries xrstor again. It will spin in this loop forever. Instead, fault in the maximum size which can be touched by XRSTOR (taken from fpstate->user_size). [ dhansen: tweak subject / changelog ]
How severe is CVE-2024-26603?
CVE-2024-26603 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2024-26603?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2024-26603?

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Source: NVD / NIST