Detect CVE-2026-48751: Incus Restricted Project Bypass Leading to Arbitrary Command Execution in Splunk
Detects exploitation of CVE-2026-48751, a critical missing authorization vulnerability (CWE-862) in Incus (github.com/lxc/incus/v7/cmd/incusd) versions prior to 7.2.0. An attacker with access to a restricted Incus project can bypass project restrictions to execute arbitrary commands on the host system, achieving container escape with a CVSS score of 9.9. A public proof-of-concept is available.
MITRE ATT&CK
SPL Detection Query
index=linux OR index=endpoint sourcetype IN ("linux:audit", "auditd", "syslog", "osquery:results")
("incusd" OR "incus")
| eval is_escape_attempt=if(match(cmdline, "(nsenter|unshare|chroot|pivot_root)"), 1, 0)
| eval is_shell_spawn=if(match(process, "^(sh|bash|zsh|fish|python[23]?|perl|ruby)$") AND parent_process IN ("incusd", "incus"), 1, 0)
| eval is_privileged_op=if(match(cmdline, "(--target.*1|--mount|--pid|--net|--uts)"), 1, 0)
| where is_escape_attempt=1 OR (is_shell_spawn=1 AND is_privileged_op=1)
| eval risk_score=case(
is_escape_attempt=1, 100,
is_shell_spawn=1 AND is_privileged_op=1, 90,
is_shell_spawn=1, 60,
true(), 50)
| where risk_score >= 80
| stats count BY host, user, process, parent_process, cmdline, risk_score, _time
| sort -risk_score, -_timeDetects Incus restricted project bypass exploitation by identifying shell spawning and namespace manipulation activities originating from incusd processes on Linux hosts.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Authorized system administrators using incus exec for legitimate container operations
- CI/CD pipelines that use Incus containers and regularly execute commands inside them
- Monitoring agents that inspect container processes via incusd
- Lab or development environments with intentionally permissive Incus project configurations
Other platforms for CVE-2026-48751
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 1Incus Restricted Project Shell Escape via Exec API
Expected signal: Process audit logs showing incusd spawning /bin/sh or nsenter with parent PID of incusd; auditd EXECVE records for nsenter or chroot with ppid matching incusd; /proc/<pid>/ns/pid symlink pointing to host PID namespace
- Test 2Verify Incus Vulnerable Version Present
Expected signal: Process execution events for incusd --version and incus project list; API calls to /1.0/projects and /1.0/instances visible in incusd access logs
- Test 3Container Escape via Host Namespace Entry Post-Bypass
Expected signal: Auditd SYSCALL records for nsenter (execve), unshare, clone syscalls; /proc/<pid>/ns/pid and /proc/<pid>/ns/mnt symlinks showing target namespace 1 (host init); process tree showing sh/bash with host-level PID namespace confirmed by NSpid field in /proc/self/status
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