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CVE-2026-23134

N/A Unknown
Denial of Service

📋 TL;DR

A race condition vulnerability in the Linux kernel's slab allocator that can cause kernel panics on PREEMPT_RT (Real-Time) kernels. When kmalloc_nolock() is called from contexts with disabled preemption (like BPF programs from tracepoints), it attempts to acquire a sleeping lock, triggering a BUG condition. This affects systems running PREEMPT_RT kernels with specific configurations.

💻 Affected Systems

Products:
  • Linux kernel
Versions: Specific versions with the vulnerable code before fixes were applied
Operating Systems: Linux distributions using PREEMPT_RT kernel patches
Default Config Vulnerable: ✅ No
Notes: Only affects systems with PREEMPT_RT kernel configuration; standard Linux kernels are not vulnerable.

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:
  1. Review the CVE details at NVD
  2. Check vendor security advisories for your specific version
  3. Test if the vulnerability is exploitable in your environment
  4. Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash and denial of service, potentially disrupting critical real-time operations.

🟠

Likely Case

System instability or crashes when BPF programs run from tracepoints with preemption disabled on PREEMPT_RT kernels.

🟢

If Mitigated

No impact on standard Linux kernels; limited to specific PREEMPT_RT configurations.

🌐 Internet-Facing: LOW - Requires local access and specific kernel configuration.
🏢 Internal Only: MEDIUM - Could affect internal systems running PREEMPT_RT kernels with vulnerable configurations.

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: MEDIUM

Exploitation requires local access and ability to trigger specific kernel code paths with preemption disabled.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Kernel versions containing commits 99a3e3a1cfc93b8fe318c0a3a5cfb01f1d4ad53c and f60ba4a97ae3f94e4818722ed2e4d260bbb17b44

Vendor Advisory: https://git.kernel.org/stable/c/99a3e3a1cfc93b8fe318c0a3a5cfb01f1d4ad53c

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Rebuild kernel if using custom kernel. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable PREEMPT_RT

all

Switch to standard kernel configuration without real-time patches

# Reconfigure kernel without PREEMPT_RT options
# Rebuild and install kernel

Avoid vulnerable code paths

all

Prevent BPF programs from running in tracepoints with preemption disabled

# Modify BPF program configurations
# Adjust tracepoint usage

🧯 If You Can't Patch

  • Monitor system logs for kernel panic/BUG messages related to slab allocation
  • Implement strict access controls to prevent unauthorized local code execution

🔍 How to Verify

Check if Vulnerable:

Check kernel configuration for PREEMPT_RT and examine kernel version against patched versions

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits and test BPF programs with tracepoints

📡 Detection & Monitoring

Log Indicators:

  • Kernel panic messages
  • BUG: sleeping function called from invalid context
  • slab allocation errors

Network Indicators:

  • None - local vulnerability only

SIEM Query:

source="kernel" AND ("sleeping function called from invalid context" OR "slab" OR "kmalloc_nolock")

📊 Metadata

CVE ID: CVE-2026-23134
CVSS v3 Score: N/A (Unknown)
Published: February 14, 2026
Last Updated: February 18, 2026

🔗 References

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