high CVSS 7.8 EPSS <0.1%

CVE-2024-39277·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: dma-mapping: benchmark: handle NUMA_NO_NODE correctly cpumask_of_node() can be called for NUMA_NO_NODE inside do_map_benchmark() resulting in the following sanitizer report: UBSAN: array-index-out-of-bounds in ./arch/x86/include/asm/topology.h:72:28 index -1 is out of range for type 'cpumask [64][1]' CPU: 1 PID: 990 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #29 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:117) ubsan_epilogue (lib/ubsan.c:232) __ubsan_handle_out_of_bounds (lib/ubsan.c:429) cpumask_of_node (arch/x86/include/asm/topology.h:72) [inline] do_map_benchmark (kernel/dma/map_benchmark.c:104) map_benchmark_ioctl (kernel/dma/map_benchmark.c:246) full_proxy_unlocked_ioctl (fs/debugfs/file.c:333) __x64_sys_ioctl (fs/ioctl.c:890) do_syscall_64 (arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Use cpumask_of_node() in place when binding a kernel thread to a cpuset of a particular node. Note that the provided node id is checked inside map_benchmark_ioctl(). It's just a NUMA_NO_NODE case which is not handled properly later. Found by Linux Verification Center (linuxtesting.org).

Severity
high
Software
Kernel
Fixed in
6.9.4
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 24% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2024-39277 scores 7.8 on CVSS, so a successful attack would be serious — but at <0.1%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 6.7

Until: 6.9.4

Fixed in: 6.9.4

How to fix this CVE

Update your Linux kernel to version 6.9.4 or later to resolve this memory safety issue affecting DMA mapping benchmarking. The vulnerability allows out-of-bounds array access when handling NUMA_NO_NODE cases, which can trigger undefined behavior. Apply the kernel update through your distribution's package manager and reboot your system to complete remediation.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check your kernel version with: uname -r
  2. Verify if your version falls within the vulnerable range (6.7 to 6.9.3) by comparing against kernel release dates at kernel.org
  3. Review system logs for UBSAN (Undefined Behavior Sanitizer) messages: grep -i 'UBSAN\|array-index-out-of-bounds' /var/log/kern.log or journalctl -b | grep -i 'UBSAN'
  4. Confirm the update was applied by running uname -r again and verifying it shows version 6.9.4 or later

FAQ

What is CVE-2024-39277?

CVE-2024-39277 is a kernel memory safety vulnerability in DMA mapping benchmarking code where NUMA_NO_NODE values are not properly validated before being used to index into CPU mask arrays, leading to out-of-bounds access.

Is CVE-2024-39277 being actively exploited?

No, CVE-2024-39277 is not actively exploited in the wild and has no public exploit available. This vulnerability requires local kernel module/ioctl access to trigger.

What versions of Kernel are affected by CVE-2024-39277?

Linux kernel versions 6.7.0 through 6.9.3 are affected. Version 6.9.4 and later contain the fix.

How do I check if my server is vulnerable to CVE-2024-39277?

Run 'uname -r' and compare your kernel version number against the affected range (6.7.x to 6.9.3). If your version is within this range, you are vulnerable.

Does Defensia detect CVE-2024-39277?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-39277 will appear in your dashboard with remediation steps.

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References

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