Arbitrary file operations via unchecked path containment
Published Aug 27, 2026 · Updated Aug 27, 2026
Path traversal in boxpositron WithContext MCP 3.0.0 through 3.0.7 allows remote attackers to read, write, or delete arbitrary files. The ingest_notes, sync_notes, and teleport_notes handlers pass caller-influenced project and derived paths to fs.readFile, fs.writeFile, and fs.unlink without a final canonical containment check. Exploitation requires access to an MCP tool handler and runs with the server process's filesystem permissions, bounding affected files to what that process can access.
Summary
What happened
Path traversal in boxpositron WithContext MCP 3.0.0 through 3.0.7 allows remote attackers to read, write, or delete arbitrary files. The ingest_notes, sync_notes, and teleport_notes handlers pass caller-influenced project and derived paths to fs.readFile, fs.writeFile, and fs.unlink without a final canonical containment check. Exploitation requires access to an MCP tool handler and runs with the server process's filesystem permissions, bounding affected files to what that process can access.
The record
- CVE
- CVE-2026-81491
- Published
- Aug 27, 2026
- Updated
- Aug 27, 2026
- Vendor
- boxpositron
- Product
- WithContext MCP
- Classifications
- CWE-22, T1485, T1005, T1565.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 27, 2026CVE publishedPublication date reported by the CVE source.
- Aug 27, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.0.0
- Affected versionversion=3.0.1
- Affected versionversion=3.0.2
- Affected versionversion=3.0.3
- Affected versionversion=3.0.4
- Affected versionversion=3.0.5
- Affected versionversion=3.0.6
- Affected versionversion=3.0.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub issue #2 reproduction requestproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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