Detect Linux Kernel Incorrect Resource Transfer Between Spheres (CVE-2026-31431) in Splunk
CVE-2026-31431 is a Linux Kernel vulnerability classified as CWE-669 (Incorrect Resource Transfer Between Spheres). The flaw allows improper transfer of resources across security boundaries within the kernel, potentially enabling privilege escalation or unauthorized memory access. This vulnerability is listed in the CISA Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. Attackers with local access may exploit this to escalate privileges to root or escape container boundaries.
MITRE ATT&CK
SPL Detection Query
index=linux_logs (sourcetype=syslog OR sourcetype=linux_secure OR sourcetype=linux_audit)
| where (source="/var/log/kern.log" OR source="/var/log/messages" OR source="/dev/log")
AND (message LIKE "%copy_to_user%" OR message LIKE "%copy_from_user%" OR message LIKE "%__copy_overflow%"
OR message LIKE "%BUG: unable to handle%" OR message LIKE "%general protection fault%"
OR message LIKE "%use-after-free%" OR message LIKE "%kernel NULL pointer%"
OR message LIKE "%out-of-bounds%")
| eval severity_level=case(
match(message, "BUG:|Oops:|kernel panic"), "critical",
match(message, "general protection|use-after-free"), "high",
true(), "medium")
| stats count AS event_count, earliest(_time) AS first_seen, latest(_time) AS last_seen, values(message) AS kernel_messages BY host, severity_level
| where event_count > 0
| sort - last_seenSplunk query to identify Linux kernel resource transfer boundary violations associated with CVE-2026-31431, correlating kernel log fault messages that indicate improper cross-sphere memory access or copy operations.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Kernel bug reports from crash reporters or automated diagnostic tools unrelated to exploitation
- Memory fault messages triggered by hardware errors or RAM issues rather than software exploitation
- Development or staging hosts running experimental kernel modules that produce intentional fault messages
Other platforms for CVE-2026-31431
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Simulate kernel copy boundary fault via /proc/kcore read attempt
Expected signal: Kernel message in dmesg showing access denial or fault; audit log SYSCALL record for 'open' or 'read' on /proc/kcore by non-root UID; possible kernel warning message about unauthorized memory access attempt
- Test 2Privilege escalation simulation via SUID binary abuse on unpatched kernel
Expected signal: Audit log SYSCALL record showing execve of test_suid with uid!=0 but euid=0; EDR process event showing SUID execution; possible AppArmor/SELinux denial log if MAC policy is enforced
- Test 3Container escape boundary test via /proc/sysrq-trigger probe
Expected signal: Host kernel log entries showing container namespace probe attempts; Docker daemon log entries for the test container; audit log entries showing file access attempts to /dev/mem or /proc/1/ from container process
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