CVE-2026-47861 Overview
CVE-2026-47861 affects Spring Integration's UDP inbound adapter component. An unauthenticated remote attacker who sends a single UDP packet to a vulnerable adapter can force the server to emit an outbound UDP datagram to an arbitrary host and port. The attacker chooses the destination, enabling reflection to internal or external targets.
The flaw permits network reconnaissance against internal services and can facilitate UDP reflection or amplification. Because the adapter accepts unauthenticated input, no credentials or user interaction are required at the network boundary.
Critical Impact
A single crafted UDP packet forces the Spring Integration server to emit an outbound datagram to any attacker-selected address and port, enabling internal network probing and traffic reflection.
Affected Products
- Spring Integration 7.1.0
- Spring Integration 7.0.0 through 7.0.5, and 6.5.0 through 6.5.10
- Spring Integration 6.4.0 through 6.4.12, and 5.5.21 and earlier
Discovery Timeline
- 2026-08-27 - CVE-2026-47861 published to NVD
- 2026-08-27 - Last updated in NVD database
Technical Details for CVE-2026-47861
Vulnerability Analysis
Spring Integration provides messaging endpoints that adapt external protocols into the Spring messaging framework. The UDP inbound adapter listens for incoming datagrams and converts them into Spring messages for downstream processing.
The vulnerable adapter honors destination information carried inside received UDP packets and issues a corresponding outbound datagram. An unauthenticated sender can therefore direct the server to transmit UDP traffic to any host and port reachable from the server.
This behavior turns the Spring Integration instance into an attacker-controlled UDP relay. Attackers can pivot to internal services normally blocked by perimeter firewalls, scan internal ports through emitted traffic, or reflect datagrams toward third-party victims. The issue is categorized as Server-Side Request Forgery (SSRF) over UDP.
Root Cause
The adapter derives outbound datagram destination fields from attacker-controlled input without validating that the target address belongs to a permitted allow-list. Trusting client-supplied routing metadata within the received packet allows an external sender to designate arbitrary destinations.
Attack Vector
Exploitation requires network reachability to the UDP port bound by the Spring Integration inbound adapter. The attacker sends one crafted UDP packet that encodes the desired target address and port. The server parses the packet and emits an outbound UDP datagram to that destination. No authentication or session state is required beyond low privileges at the network layer, per the published CVSS vector. Refer to the Spring Security advisory for CVE-2026-47861 for protocol-level details.
Detection Methods for CVE-2026-47861
Indicators of Compromise
- Outbound UDP datagrams originating from a Spring Integration host toward internal RFC1918 addresses or unexpected external hosts.
- Bursts of small, uniform UDP packets emitted shortly after receipt of an inbound datagram on the adapter port.
- Application logs showing UDP inbound adapter activity from unknown or unauthorized source addresses.
Detection Strategies
- Correlate inbound UDP datagrams to the adapter port with subsequent outbound UDP traffic from the same process to identify reflected packets.
- Baseline expected UDP destinations for the Spring Integration service and alert on deviations to new addresses or ports.
- Inspect firewall and NetFlow records for the JVM process emitting UDP traffic to internal management interfaces such as DNS, SNMP, or NTP.
Monitoring Recommendations
- Enable verbose logging on the UnicastReceivingChannelAdapter and related UDP components to capture source and destination metadata.
- Forward host and network telemetry to a centralized SIEM for correlation across inbound and outbound UDP flows.
- Monitor for scanning patterns where a single source generates many distinct destination pairs through the affected service.
How to Mitigate CVE-2026-47861
Immediate Actions Required
- Upgrade Spring Integration to a fixed release line as identified in the Spring Security advisory.
- Restrict network access to UDP inbound adapter ports using firewall rules that allow only trusted senders.
- Audit application configurations to determine whether UDP inbound adapters are enabled and required for business function.
Patch Information
Spring maintainers publish fixed versions for the 6.4.x, 6.5.x, 7.0.x, and 7.1.x branches. Consult the Spring Security advisory for CVE-2026-47861 for the exact patched release numbers and upgrade guidance. The 5.5.x branch is out of open-source support; commercial support subscribers should contact Spring for backported fixes.
Workarounds
- Disable the UDP inbound adapter if the application does not require UDP messaging endpoints.
- Place the Spring Integration host behind egress filtering that blocks outbound UDP to unintended destinations and internal management subnets.
- Bind the adapter to a network interface segregated from sensitive internal services to limit reflection targets.
# Example egress restriction using iptables to limit outbound UDP
# from the Spring Integration host to an approved destination only
iptables -A OUTPUT -p udp -d 10.0.10.25 --dport 5514 -j ACCEPT
iptables -A OUTPUT -p udp -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
