CVE-2026-14587

Unathenticated connection can hold Bolt channel open

Published Aug 5, 2026 CVSS 4.0 · 5.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
References
History
Type Values Removed Values Added
First Time appeared Neo4j neo4j
CPEs cpe:2.3:a:neo4j:neo4j:*:*:*:*:community:*:*:*
cpe:2.3:a:neo4j:neo4j:*:*:*:*:enterprise:*:*:*
Vendors & Products Neo4j neo4j
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Neo4j
Neo4j community Edition
Neo4j enterprise Edition
Vendors & Products Neo4j
Neo4j community Edition
Neo4j enterprise Edition
Type Values Removed Values Added
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
Metrics cvssV4_0

{'score': 5.5, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
Neo4j
Published
Updated
Aug 5, 2026, 6:41 PM
Reserved
Jul 3, 2026, 12:01 PM
Status
Analyzed
Published
Aug 5, 2026, 5:16 PM
Modified
Aug 28, 2026, 4:08 PM