Vulnerability · Published Aug 5, 2026 · Assigned by Neo4j
CVE-2026-14587Unathenticated connection can hold Bolt channel open
Medium 5.5
In plain English
A medium-severity security flaw in Community Edition from neo4j. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | bolt | no fix listed | UBUNTU-CVE-2026-14587 |
| Ubuntu:24.04:LTS | bolt | no fix listed | UBUNTU-CVE-2026-14587 |
| Ubuntu:26.04:LTS | bolt | no fix listed | UBUNTU-CVE-2026-14587 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| neo4j | Enterprise Edition | 2025.01 – before 2026.075.0 – before 5.26.29 |
| neo4j | Community Edition | 2025.01 – before 2026.075.0 – before 5.26.29 |
Weakness: CWE-130 · 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
References
- https://neo4j.com/security/CVE-2026-14587 vendor-advisory