Neo4j's Bolt modern handshake decoder treats an overlong capability bit mask the same way it treats a truncated bit mask. When an unauthenticated client sends a selected protocol version followed by 32 continuation bytes in the capability mask, the decoder resets the reader index and waits for more bytes instead of rejecting the protocol message and closing the channel.
Because the same unread bytes remain at the front of the decoder buffer, appending a terminating byte later does not recover the connection. The decoder re-reads the same first 32 continuation bytes, returns without producing a handshake-finalization message, and leaves the channel open.
This can be triggered before authentication by any client that can reach the Bolt connector.
Metrics
Affected Vendors & Products
References
| Link | Providers |
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| https://neo4j.com/security/CVE-2026-14587 |
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History
Wed, 05 Aug 2026 19:30:00 +0000
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ssvc
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Wed, 05 Aug 2026 18:45:00 +0000
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Neo4j
Neo4j community Edition Neo4j enterprise Edition |
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Neo4j
Neo4j community Edition Neo4j enterprise Edition |
Wed, 05 Aug 2026 17:00:00 +0000
| Type | Values Removed | Values Added |
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| Description | Neo4j's Bolt modern handshake decoder treats an overlong capability bit mask the same way it treats a truncated bit mask. When an unauthenticated client sends a selected protocol version followed by 32 continuation bytes in the capability mask, the decoder resets the reader index and waits for more bytes instead of rejecting the protocol message and closing the channel. Because the same unread bytes remain at the front of the decoder buffer, appending a terminating byte later does not recover the connection. The decoder re-reads the same first 32 continuation bytes, returns without producing a handshake-finalization message, and leaves the channel open. This can be triggered before authentication by any client that can reach the Bolt connector. | |
| Title | Unathenticated connection can hold Bolt channel open | |
| Weaknesses | CWE-130 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: Neo4j
Published:
Updated: 2026-08-05T18:41:20.229Z
Reserved: 2026-07-03T12:01:33.324Z
Link: CVE-2026-14587
Updated: 2026-08-05T18:15:47.026Z
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OpenCVE Enrichment
Updated: 2026-08-05T20:00:12Z