CVE-2023-52476

CVE-2023-52476 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: perf/x86/lbr: Filter vsyscall addresses We found that a panic can occur when a vsyscall is made while LBR sampling is active. If the vsyscall is interrupted (NMI) for perf sampling, this call sequence can occur (most recent at top): __insn_get_emulate_prefix() insn_get_emulate_prefix() insn_get_prefixes() insn_get_opcode() decode_branch_type() get_branch_type() intel_pmu_lbr_filter() intel_pmu_handle_irq() perf_event_nmi_handler() Within __insn_get_emulate_prefix() at frame 0, a macro is called: peek_nbyte_next(insn_byte_t, insn, i) Within this macro, this dereference occurs: (insn)->next_byte Inspecting registers at this point, the value of the next_byte field is the address of the vsyscall made, for example the location of the vsyscall version of gettimeofday() at 0xffffffffff600000. The access to an address in the vsyscall region will trigger an oops due to an unhandled page fault. To fix the bug, filtering for vsyscalls can be done when determining the branch type. This patch will return a "none" branch if a kernel address if found to lie in the vsyscall region.

Frequently asked questions

What is CVE-2023-52476?
In the Linux kernel, the following vulnerability has been resolved: perf/x86/lbr: Filter vsyscall addresses We found that a panic can occur when a vsyscall is made while LBR sampling is active. If the vsyscall is interrupted (NMI) for perf sampling, this call sequence can occur (most recent at top): __insn_get_emulate_prefix() insn_get_emulate_prefix() insn_get_prefixes() insn_get_opcode() decode_branch_type() get_branch_type() intel_pmu_lbr_filter() intel_pmu_handle_irq() perf_event_nmi_handler() Within __insn_get_emulate_prefix() at frame 0, a macro is called: peek_nbyte_next(insn_byte_t, insn, i) Within this macro, this dereference occurs: (insn)->next_byte Inspecting registers at this point, the value of the next_byte field is the address of the vsyscall made, for example the location of the vsyscall version of gettimeofday() at 0xffffffffff600000. The access to an address in the vsyscall region will trigger an oops due to an unhandled page fault. To fix the bug, filtering for vsyscalls can be done when determining the branch type. This patch will return a "none" branch if a kernel address if found to lie in the vsyscall region.
How severe is CVE-2023-52476?
CVE-2023-52476 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-52476 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-52476?
CVE-2023-52476 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-52476?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2023-52476 have an EU (EUVD) identifier?
Yes. CVE-2023-52476 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-57101.
When was CVE-2023-52476 published?
CVE-2023-52476 was published on 2024-02-29 and last updated on 2026-06-17.

References

Affected products (6)

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