CVE-2026-14587 Unathenticated connection can hold Bolt channel open
Unauthenticated attackers can exhaust server resources by holding Bolt channels open via malformed handshake packets, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-14587?
CVE-2026-14587 is a medium-severity denial of service vulnerability in neo4j Community Edition, published on 5 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-130
Which versions are affected by CVE-2026-14587?
2 open source packages ship an affected version, including neo4j and neo4j-enterprise. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
neo4j Bitnami | From 5.0.0 | 5.26.29, 2026.7.0 |
neo4j-enterprise Bitnami | From 5.0.0 | 5.26.29, 2026.7.0 |
Products include Neo4j Neo4j.
How do I fix CVE-2026-14587?
Upgrade neo4j to a fixed version for your release line: 5.26.29 or 2026.7.0.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-14587 being exploited?
There is no known exploitation of CVE-2026-14587 in the wild and no public exploit code.
Other vulnerabilities in neo4j Community Edition
- CVE-2021-34371 Deserialization of Untrusted Data in Neo4j
- CVE-2018-18389 Incorrect access control in Neo4j Enterprise Database Server via LDAP authentication
- CVE-2013-7259 Neo4J vulnerable to Cross-Site Request Forgery
- CVE-2024-34517 Neo4j Cypher component mishandles IMMUTABLE privileges
- CVE-2026-1471 Caching of authentication context
Sources
Also known as BIT-neo4j-2026-14587, BIT-neo4j-enterprise-2026-14587, GHSA-cwvv-9488-x4h5, MINI-2m62-8fpw-8j5p, MINI-2wpp-c69r-853x, MINI-48vw-8qw4-p8g8 and 11 more.