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CVE-2026-35402

mcp-neo4j-cypher: SSRF and Data Modification via read_only Mode Bypass Through CALL Procedures

2.3 LowFix available

mcp-neo4j-cypher is an MCP server for executing Cypher queries against Neo4j databases. In versions prior to 0.6.0, the read_only mode enforcement can be bypassed using APOC CALL procedures, potentially allowing unauthorized write operations or server-side request forgery. This issue is fixed in version 0.6.0.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
None

Exploit likelihood

0.26%Up 0.2 points since Apr 18, 2026
90%50%10%1%

What each source reports

CVE List Score used 2.3

mcp-neo4j-cypher: SSRF and Data Modification via read_only Mode Bypass Through CALL Procedures

mcp-neo4j-cypher is an MCP server for executing Cypher queries against Neo4j databases. In versions prior to 0.6.0, the read_only mode enforcement can be bypassed using APOC CALL procedures, potentially allowing unauthorized write operations or server-side request forgery. This issue is fixed in version 0.6.0.

Record
CVE-2026-35402
CVSS 4.0
2.3 LowCVSS: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-284
Updated
2026-11-02
EUVDEUVD-2026-23518 2.3

mcp-neo4j-cypher is an MCP server for executing Cypher queries against Neo4j databases. In versions prior to 0.6.0, the read_only mode enforcement can be bypassed using APOC CALL procedures, potentially allowing unauthorized write operations or server-side request forgery. This issue is fixed in version 0.6.0.

Record
EUVD-2026-23518
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-x3cv-r3g3-fpg9 2.3

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.enabled is false by default
    • apoc.import.file.use_neo4j_config is true by default to restrict file imports to the import folder

Credits

We want to publicly recognise the contribution of Yotam Perkal from Pluto Security.

Record
GHSA-x3cv-r3g3-fpg9
CVSS 4.0
2.3 LowCVSS: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-284
Updated
2026-11-02
NVD 2.3

mcp-neo4j-cypher is an MCP server for executing Cypher queries against Neo4j databases. In versions prior to 0.6.0, the read_only mode enforcement can be bypassed using APOC CALL procedures, potentially allowing unauthorized write operations or server-side request forgery. This issue is fixed in version 0.6.0.

Record
CVE-2026-35402
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness
CWE-284
Updated
2026-11-02
OSV 2.3

mcp-neo4j-cypher: SSRF and Data Modification via read_only Mode Bypass Through CALL Procedures

mcp-neo4j-cypher is an MCP server for executing Cypher queries against Neo4j databases. In versions prior to 0.6.0, the read_only mode enforcement can be bypassed using APOC CALL procedures, potentially allowing unauthorized write operations or server-side request forgery. This issue is fixed in version 0.6.0.

Record
CVE-2026-35402
CVSS 4.0
2.3 LowCVSS: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-284
Updated
2026-11-02
OSVGHSA-x3cv-r3g3-fpg9 2.3

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.enabled is false by default
    • apoc.import.file.use_neo4j_config is true by default to restrict file imports to the import folder

Credits

We want to publicly recognise the contribution of Yotam Perkal from Pluto Security.

Record
GHSA-x3cv-r3g3-fpg9
CVSS 4.0
2.3 LowCVSS: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-284
Updated
2026-11-02
OSVPYSEC-2026-2626 2.3

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.enabled is false by default
    • apoc.import.file.use_neo4j_config is true by default to restrict file imports to the import folder

Credits

We want to publicly recognise the contribution of Yotam Perkal from Pluto Security.

Record
PYSEC-2026-2626
CVSS 4.0
2.3 LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
mcp-neo4j-cypher
PyPI
 before 0.6.0
0.6.0
mcp-neo4j-cypher
PyPI
 before 0.6.0, plus listed versions
0.1.10.2.00.2.10.2.20.2.3
Show 9 moreShow less
0.2.40.3.00.3.10.4.00.4.10.5.00.5.10.5.20.5.3
0.6.0

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-35402 is a low vulnerability (CVSS 2.3) in Neo4j-contrib Mcp-neo4j, published April 17, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.26%, the 18th percentile. Fixed in mcp-neo4j-cypher 0.6.0.

References

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