high CVSS 7.8 EPSS <0.1%

CVE-2024-50203·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fix address emission with tag-based KASAN enabled When BPF_TRAMP_F_CALL_ORIG is enabled, the address of a bpf_tramp_image struct on the stack is passed during the size calculation pass and an address on the heap is passed during code generation. This may cause a heap buffer overflow if the heap address is tagged because emit_a64_mov_i64() will emit longer code than it did during the size calculation pass. The same problem could occur without tag-based KASAN if one of the 16-bit words of the stack address happened to be all-ones during the size calculation pass. Fix the problem by assuming the worst case (4 instructions) when calculating the size of the bpf_tramp_image address emission.

Severity
high
Software
Kernel
Fixed in
6.11.6
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 9% 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-2024-50203 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: 6.11

Until: 6.11.6

Fixed in: 6.11.6

How to fix this CVE

Update your Linux kernel to version 6.11.6 or later to resolve a heap buffer overflow vulnerability in the ARM64 BPF trampoline code generation when tag-based KASAN is enabled. This vulnerability could allow local privilege escalation through improperly calculated instruction emission during BPF program compilation. Apply the kernel update immediately and reboot your system.

sudo dnf update kernel kernel-devel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to check your current kernel version and confirm if it falls within the vulnerable range (6.11.0 to 6.11.5)
  2. Check if BPF and KASAN are enabled in your kernel config: grep -i 'CONFIG_BPF\|CONFIG_KASAN' /boot/config-$(uname -r)
  3. Monitor dmesg for heap corruption warnings or BPF-related errors: dmesg | grep -i 'heap\|bpf\|overflow\|kasan'
  4. After patching, verify the new kernel version with 'uname -r' and confirm it reports version 6.11.6 or higher

FAQ

What is CVE-2024-50203?

This vulnerability is a heap buffer overflow in the Linux kernel's ARM64 BPF code generator that occurs when tag-based KASAN is enabled, caused by incorrect size calculation during instruction emission for BPF trampoline function calls.

Is CVE-2024-50203 being actively exploited?

No, there are currently no public exploits or active exploitation reports for this vulnerability in the wild according to CISA threat data.

What versions of Kernel are affected by CVE-2024-50203?

Linux kernel versions 6.11.0 through 6.11.5 are vulnerable; version 6.11.6 and later contain the fix.

How do I check if my server is vulnerable to CVE-2024-50203?

Run 'uname -r' to get your kernel version. If it returns a version between 6.11.0 and 6.11.5 inclusive, your system is vulnerable.

Does Defensia detect CVE-2024-50203?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2024-50203 will appear in your dashboard with remediation steps.

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References

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