Neo4j Labs MCP Servers: SSRF and Data Modification via read_only Mode Bypass Through CALL Procedures
Summary
The read_only mode in mcp-neo4j-cypher versions prior to 0.6.0 can be bypassed using CALL procedures.
Details
Impact
The enforcing of read_only mode in vulnerable versions could be bypassed by certain APOC procedures.
Patches
v0.6.0 release hardened the checks around the mode. The only way to guarantee the server actions is to limit the permissions of the db credentials available to the server.
Notes
Impacts for server-side request forgery vulnerabilities may depend on both the configuration of the vulnerable system as well as the presence of other systems in the environment that could be accessed as part of exploitation.
Recommended hardening
- Limit the apoc procedures to what's required
- Manage data loading privileges
- Don't relax the default settings without compensating controls
apoc.import.file.enabledisfalseby defaultapoc.import.file.use_neo4j_configistrueby default to restrict file imports to the import folder
Credits
We want to publicly recognise the contribution of Yotam Perkal from Pluto Security.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | mcp-neo4j-cypher | < 0.6.0 | 0.6.0 |
References
- https://github.com/neo4j-contrib/mcp-neo4j/security/advisories/GHSA-x3cv-r3g3-fpg9
- https://nvd.nist.gov/vuln/detail/CVE-2026-35402
- https://github.com/neo4j-contrib/mcp-neo4j
- https://github.com/neo4j-contrib/mcp-neo4j/releases/tag/mcp-neo4j-cypher-v0.6.0
- https://pypi.org/project/mcp-neo4j-cypher
- https://github.com/advisories/GHSA-x3cv-r3g3-fpg9
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N- Weakness (CWE)
CWE-284- Platform
- Python (PyPI)
- Package
mcp-neo4j-cypher- Disclosed
- 17.04.2026
- Updated
- 11.10.2026 14:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2626 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-x3cv-r3g3-fpg9 - CC BY 4.0
Vulnerability history: mcp-neo4j-cypher
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 09.2025 04.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Low 1
Disclosures per year
- 2025: 1
- 2026: 1
-
Neo4j Labs MCP Servers: SSRF and Data Modification via read_only Mode Bypass Through CALL Procedures this entry
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