# [CRIT] [GHSA / CRITICAL] CVE-2026-46703: Boxlite: Path Traversal Vulnerability Leads to Arbitrary File Write on the Host

**Source:** GitHub Security Advisories
**Published:** 2026-05-21
**Article:** https://github.com/advisories/GHSA-f396-4rp4-7v2j

## Threat Profile

Boxlite: Path Traversal Vulnerability Leads to Arbitrary File Write on the Host

#### Summary

Boxlite is a sandbox service that allows users to create lightweight virtual machines (Boxes) and run OCI containers within them. Boxlite allows users to specify the OCI image used by containers in the sandbox. However, when processing tar entries in OCI images, Boxlite does not account for the possibility that entries may be symlinks pointing to absolute paths. An attacker can craft a malicious OCI im…

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-46703`
- **SHA256:** `b673b4e3400c71bd72464c98610c952e2164f70f946873b82adf3e6212851d54`

## MITRE ATT&CK Techniques

- **T1190** — Exploit Public-Facing Application
- **T1027** — Obfuscated Files or Information
- **T1204.002** — User Execution: Malicious File
- **T1611** — Escape to Host
- **T1574** — Hijack Execution Flow
- **T1083** — File and Directory Discovery
- **T1098.004** — Account Manipulation: SSH Authorized Keys

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### OCI image extraction creates symlink with absolute path target (CWE-61 primitive)

`UC_223_3` · phase: **exploit** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where Filesystem.process_name="boxlite" AND Filesystem.action IN ("created","symlink_created") AND (Filesystem.file_path="/etc/*" OR Filesystem.file_path="/root/*" OR Filesystem.file_path="/home/*" OR Filesystem.file_path="/var/spool/cron/*" OR Filesystem.file_path="/etc/cron.d/*" OR Filesystem.file_path="/etc/sudoers.d/*" OR Filesystem.file_path="/etc/systemd/system/*") by Filesystem.dest Filesystem.process_name Filesystem.file_path Filesystem.action
| `drop_dm_object_name(Filesystem)`
| convert ctime(firstTime) ctime(lastTime)
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName =~ "boxlite"
| where ActionType in~ ("FileCreated", "SymbolicLinkCreated")
| where FolderPath startswith "/etc/"
   or FolderPath startswith "/root/"
   or FolderPath startswith "/home/"
   or FolderPath startswith "/var/spool/cron/"
   or FolderPath startswith "/etc/cron.d/"
   or FolderPath startswith "/etc/sudoers.d/"
   or FolderPath startswith "/etc/systemd/system/"
| project Timestamp, DeviceName, ActionType, FolderPath, FileName, InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath, AdditionalFields
| order by Timestamp desc
```

### Boxlite sandbox writes to SSH authorized_keys (post-exploit RCE pivot)

`UC_223_4` · phase: **install** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where Filesystem.process_name="boxlite" AND (Filesystem.file_name="authorized_keys" OR Filesystem.file_path="*/.ssh/authorized_keys*") by Filesystem.dest Filesystem.process_name Filesystem.file_path Filesystem.action
| `drop_dm_object_name(Filesystem)`
| convert ctime(firstTime) ctime(lastTime)
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName =~ "boxlite"
| where FileName =~ "authorized_keys" or FolderPath has "/.ssh/authorized_keys"
| where ActionType in~ ("FileCreated", "FileModified", "SymbolicLinkCreated")
| project Timestamp, DeviceName, ActionType, FolderPath, FileName, InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath, AdditionalFields
| order by Timestamp desc
```

### Article-specific behavioural hunt — [GHSA / CRITICAL] CVE-2026-46703: Boxlite: Path Traversal Vulnerability Leads to

`UC_223_2` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-46703: Boxlite: Path Traversal Vulnerability Leads to ```
| tstats `summariesonly` count earliest(_time) AS firstTime latest(_time) AS lastTime
    from datamodel=Endpoint.Processes
    where (Processes.process_name IN ("poc_symlink_escape.py"))
    by Processes.dest, Processes.user, Processes.process_name,
       Processes.process, Processes.parent_process_name, Processes.process_path
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| append [
| tstats `summariesonly` count
    from datamodel=Endpoint.Filesystem
    where Filesystem.action IN ("created","modified")
      AND (Filesystem.file_path="*/usr/passwd*" OR Filesystem.file_path="*/etc/passwd*" OR Filesystem.file_path="*/usr/bin/env*" OR Filesystem.file_path="*/tmp/poc/pwned.txt*" OR Filesystem.file_path="*/tmp/boxlite_host_escape/pwned.txt*" OR Filesystem.file_path="*/tmp/malicious_oci_layout*" OR Filesystem.file_path="*/tmp/boxlite_host_escape/*" OR Filesystem.file_path="*/tmp/boxlite_host_escape*" OR Filesystem.file_name IN ("poc_symlink_escape.py"))
    by Filesystem.dest, Filesystem.user, Filesystem.process_name,
       Filesystem.file_path, Filesystem.file_name
| `drop_dm_object_name(Filesystem)`
]
```

**Defender KQL:**
```kql
// Article-specific bespoke detection — [GHSA / CRITICAL] CVE-2026-46703: Boxlite: Path Traversal Vulnerability Leads to
// Hunts the actual binaries / paths / commandline fragments named
// in the article instead of a generic technique-class template.
DeviceProcessEvents
| where Timestamp > ago(30d)
| where (FileName in~ ("poc_symlink_escape.py"))
| project Timestamp, DeviceName, AccountName, FileName,
          FolderPath, ProcessCommandLine,
          InitiatingProcessFileName, InitiatingProcessCommandLine
| order by Timestamp desc

// File-creation events for the named binaries / paths
DeviceFileEvents
| where Timestamp > ago(30d)
| where ActionType in ("FileCreated","FileModified")
| where (FolderPath has_any ("/usr/passwd", "/etc/passwd", "/usr/bin/env", "/tmp/poc/pwned.txt", "/tmp/boxlite_host_escape/pwned.txt", "/tmp/malicious_oci_layout", "/tmp/boxlite_host_escape/", "/tmp/boxlite_host_escape") or FileName in~ ("poc_symlink_escape.py"))
| project Timestamp, DeviceName, AccountName, FolderPath,
          FileName, ActionType, InitiatingProcessFileName,
          InitiatingProcessCommandLine
| order by Timestamp desc
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-46703`

- **File hash IOCs — endpoint file/process match** ([template](../_TEMPLATES.md#hash-ioc)) — phase: **install**, confidence: **High**
  - file hash IOC(s): `b673b4e3400c71bd72464c98610c952e2164f70f946873b82adf3e6212851d54`


## Why this matters

Severity classified as **CRIT** based on: CVE present, IOCs present, 5 use case(s) fired, 7 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.