Linux Kernel
CVE-2024-26674
HIGH
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.1 (HIGH). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A local attacker with access to the system could write data beyond allocated buffer boundaries leading to code execution or crashes. |
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Alert meAnalysisAI
In the Linux kernel, the following vulnerability has been resolved: x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups During memory error injection test on kernels >= v6.4, the kernel. Rated high severity (CVSS 7.1), this vulnerability is low attack complexity. This Out-of-bounds Write vulnerability could allow attackers to write data beyond allocated buffer boundaries leading to code execution or crashes.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).
Affects your stack
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Technical ContextAI · show details
This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. In the Linux kernel, the following vulnerability has been resolved: x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups During memory error injection test on kernels >= v6.4, the kernel panics like below. However, this issue couldn't be reproduced on kernels <= v6.3. mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134 mce: [Hardware Error]: RIP 10:<ffffffff821b9776> {__get_user_nocheck_4+0x6/0x20} mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86 mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490 mce: [Hardware Error]: Run the above through 'mcelog --ascii' mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel Kernel panic - not syncing: Fatal local machine check The MCA code can recover from an in-kernel #MC if the fixup type is EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT the only thing that is raised for an in-kernel #MC is a panic. ex_handler_uaccess() would warn if users gave a non-canonical addresses (with bit 63 clear) to {get, put}_user(), which was unexpected. Therefore, commit b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()") replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user() fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic. Commit 6014bc27561f ("x86-64: make access_ok() independent of LAM") added the check gp_fault_address_ok() right before the WARN_ONCE() in ex_handler_uaccess() to not warn about non-canonical user addresses due to LAM. With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user() exception fixups in order to be able to handle in-kernel MCEs correctly again. [ bp: Massage commit message. ] Affected products include: Linux Linux Kernel.
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Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
In the Linux kernel, the following vulnerability has been resolved:
x86/lib: Revert to _ASM_EXTABLE_UA() for {get,put}_user() fixups
During memory error injection test on kernels >= v6.4, the kernel panics like below. However, this issue couldn't be reproduced on kernels <= v6.3.
mce: [Hardware Error]: CPU 296: Machine Check Exception: f Bank 1: bd80000000100134 mce: [Hardware Error]: RIP 10:<ffffffff821b9776> {__get_user_nocheck_4+0x6/0x20} mce: [Hardware Error]: TSC 411a93533ed ADDR 346a8730040 MISC 86 mce: [Hardware Error]: PROCESSOR 0:a06d0 TIME 1706000767 SOCKET 1 APIC 211 microcode 80001490 mce: [Hardware Error]: Run the above through 'mcelog --ascii' mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel Kernel panic - not syncing: Fatal local machine check
The MCA code can recover from an in-kernel #MC if the fixup type is EX_TYPE_UACCESS, explicitly indicating that the kernel is attempting to access userspace memory. However, if the fixup type is EX_TYPE_DEFAULT the only thing that is raised for an in-kernel #MC is a panic.
ex_handler_uaccess() would warn if users gave a non-canonical addresses (with bit 63 clear) to {get, put}_user(), which was unexpected.
Therefore, commit
b19b74bc99b1 ("x86/mm: Rework address range check in get_user() and put_user()")
replaced _ASM_EXTABLE_UA() with _ASM_EXTABLE() for {get, put}_user() fixups. However, the new fixup type EX_TYPE_DEFAULT results in a panic.
Commit
6014bc27561f ("x86-64: make access_ok() independent of LAM")
added the check gp_fault_address_ok() right before the WARN_ONCE() in ex_handler_uaccess() to not warn about non-canonical user addresses due to LAM.
With that in place, revert back to _ASM_EXTABLE_UA() for {get,put}_user() exception fixups in order to be able to handle in-kernel MCEs correctly again.
[ bp: Massage commit message. ]
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Affected Products (CPE)NVD
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