How severe is CVE-2026-35402?

No CVSS score has been assigned to CVE-2026-35402 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-35402?

CVE-2026-35402 affects the following packages: mcp-neo4j-cypher (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-35402?

Update mcp-neo4j-cypher to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35402 is resolved across your whole dependency graph.

How do I detect CVE-2026-35402 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mcp-neo4j-cypher, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-35402 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-35402 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-35402 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-35402?

CVE-2026-35402 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 18th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-35402?

CVE-2026-35402 is classified as CWE-284 (CWE-284). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-35402 published, and has it been updated?

CVE-2026-35402 was published on April 17, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-35402 — mcp-neo4j-cypher

CVE-2026-35402 is a CWE-284 vulnerability in mcp-neo4j-cypher. A fix is available for mcp-neo4j-cypher — see the affected versions and patch details below.

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

Also known asGHSA-x3cv-r3g3-fpg9PYSEC-2026-2626

Published

Apr 17, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-35402.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk-0.12%

Lower risk than most CVEs18th percentile — riskier than 18% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍mcp-neo4j-cypher

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`mcp-neo4j-cypher`	all versions	0.6.0`pip install --upgrade 'mcp-neo4j-cypher==0.6.0'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mcp-neo4j-cypher, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mcp-neo4j-cypher to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-35402 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

### 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 sys

O3 Security · Impact-Aware SCA

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