CVE-2024-43840

CVE-2024-43840 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: bpf, arm64: Fix trampoline for BPF_TRAMP_F_CALL_ORIG When BPF_TRAMP_F_CALL_ORIG is set, the trampoline calls __bpf_tramp_enter() and __bpf_tramp_exit() functions, passing them the struct bpf_tramp_image *im pointer as an argument in R0. The trampoline generation code uses emit_addr_mov_i64() to emit instructions for moving the bpf_tramp_image address into R0, but emit_addr_mov_i64() assumes the address to be in the vmalloc() space and uses only 48 bits. Because bpf_tramp_image is allocated using kzalloc(), its address can use more than 48-bits, in this case the trampoline will pass an invalid address to __bpf_tramp_enter/exit() causing a kernel crash. Fix this by using emit_a64_mov_i64() in place of emit_addr_mov_i64() as it can work with addresses that are greater than 48-bits.

Frequently asked questions

What is CVE-2024-43840?
In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fix trampoline for BPF_TRAMP_F_CALL_ORIG When BPF_TRAMP_F_CALL_ORIG is set, the trampoline calls __bpf_tramp_enter() and __bpf_tramp_exit() functions, passing them the struct bpf_tramp_image *im pointer as an argument in R0. The trampoline generation code uses emit_addr_mov_i64() to emit instructions for moving the bpf_tramp_image address into R0, but emit_addr_mov_i64() assumes the address to be in the vmalloc() space and uses only 48 bits. Because bpf_tramp_image is allocated using kzalloc(), its address can use more than 48-bits, in this case the trampoline will pass an invalid address to __bpf_tramp_enter/exit() causing a kernel crash. Fix this by using emit_a64_mov_i64() in place of emit_addr_mov_i64() as it can work with addresses that are greater than 48-bits.
How severe is CVE-2024-43840?
CVE-2024-43840 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-2024-43840 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-43840?
CVE-2024-43840 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-43840?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-43840 have an EU (EUVD) identifier?
Yes. CVE-2024-43840 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-40490.
When was CVE-2024-43840 published?
CVE-2024-43840 was published on 2024-08-17 and last updated on 2026-06-17.

References

Affected products (1)

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