Detect CVE-2026-33646: Mise Arbitrary Code Execution via Tera Template Injection in .tool-versions in CrowdStrike LogScale
Detects exploitation of CVE-2026-33646, a critical trust bypass vulnerability in mise (formerly rtx) versions prior to 2026.3.10. Attackers can embed Tera template directives inside .tool-versions files to achieve arbitrary code execution when mise processes the file, bypassing trust checks. CVSS 9.6. PoC public.
MITRE ATT&CK
- Tactic
- Execution Persistence Defense Evasion
LogScale Detection Query
#event_simpleName IN ("FileWritten", "ProcessRollup2")
| $FileWritten = ($event_simpleName = "FileWritten" AND TargetFileName MATCHES "\.tool-versions$")
| $MiseExec = ($event_simpleName = "ProcessRollup2" AND (ImageFileName MATCHES "(^|/)mise$" OR ImageFileName MATCHES "(^|\\\\)mise\.exe$") AND (CommandLine MATCHES "install|trust|run|exec|shell"))
| groupby([aid, ComputerName], function=[collect(TargetFileName, limit=5), collect(CommandLine, limit=5), count($FileWritten, as=file_writes), count($MiseExec, as=mise_execs)])
| where file_writes > 0 AND mise_execs > 0
| sort(mise_execs, order=desc)
| select([ComputerName, aid, file_writes, mise_execs, TargetFileName, CommandLine])CrowdStrike Falcon LogScale CQL query correlating .tool-versions file writes with mise process execution events by agent ID, surfacing hosts where both activities co-occurred.
Data Sources
Required Tables
False Positives & Tuning
- Developer workstations where mise is the primary version manager and .tool-versions files are frequently updated
- Build agents in CI/CD pipelines that use mise for runtime environment setup
- Pair programming or shared workstation sessions with simultaneous file edits and tool invocations
Other platforms for CVE-2026-33646
Testing Methodology
Validate this detection against 4 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 1Inject Tera system() call into .tool-versions and invoke mise install
Expected signal: File write event for .tool-versions, followed by mise process launch, followed by child process executing 'id' or shell writing to /tmp/mise-pwned.txt
- Test 2Malicious .tool-versions via Git Clone Simulation
Expected signal: Directory creation, .tool-versions file write by shell (not interactive mise), then mise process launch with install argument
- Test 3mise trust bypass via template in project-local .tool-versions
Expected signal: osascript child process spawned from mise with suspicious arguments, .tool-versions read by mise process
- Test 4Enumerate environment variables via Tera template injection
Expected signal: File write of .tool-versions, mise process launch, child write to /tmp/mise-env-leak.txt containing environment variable value
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