CVE-2026-47863— Reactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flush
Quick assessment
Affected
Spring Reactor Core
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Reactor Core 中，启用公平背压（fairBackpressure）并使用 操作符的应用程序存在拒绝服务（DoS）漏洞。 受影响版本： Reactor Core 3.8.0 至 3.8.6 Reactor Core 3.7.19 及更早版本
Possible ATT&CK Techniques 1 AI
T1499 · Endpoint Denial of Service
Get alerts for future matching vulnerabilities
Log in to subscribe
I. Basic Information for CVE-2026-47863
Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗
Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.
Vulnerability Title
Reactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flush
Source: CVE Program / CVE List V5
Vulnerability Description
In Reactor Core, applications that use the Flux.bufferTimeout operator with fairBackpressure enabled are vulnerable to a Denial of Service (DoS) condition.
Reactor Core 3.8.0 - 3.8.6
Reactor Core 3.7.19 and earlier
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Spring | Reactor Core | 3.8.0 ~ 3.8.6 | - |
|
II. Public POCs for CVE-2026-47863
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
Premium
No public POC found.
Login to generate AI POCIII. Intelligence Information for CVE-2026-47863
请登录查看更多情报信息。
Vendor Pages for CVE-2026-47863 (1)
Same Patch Batch · Spring · 2026-08-26 · 20 CVEs total
| CVE-2026-47852 | 7.5 HIGH | Predictable cache directory location allows local ONNX model substitution in Spring AI |
| CVE-2026-47851 | 7.5 HIGH | Unbounded recursion over attacker-controlled PDF outline tree in Spring AI PDF Document Re |
| CVE-2026-47841 | 7.4 HIGH | WebAuthn User Verification Bypass via Session Serialization |
| CVE-2026-47836 | 7.2 HIGH | Spring Cloud Config Server Susceptible To TOCTOU Attack When Using SVN |
| CVE-2026-47837 | 6.8 MEDIUM | Spring Cloud Config Server Monitor Endpoint Does Not Validate Webhook Requests |
| CVE-2026-47842 | 6.5 MEDIUM | Deterministic AES/CBC Encryption in Spring Security AesBytesEncryptor Allows Ciphertext Co |
| CVE-2026-47860 | 6.5 MEDIUM | Unbounded decompression of attacker-supplied compressed message bodies |
| CVE-2026-47861 | 6.3 MEDIUM | UDP adapter sends ack to attacker-supplied host:port parsed from packet body, even when ac |
| CVE-2026-47856 | 6.3 MEDIUM | JsonToObjectTransformer resolves the json__TypeId__ message header to an arbitrary class w |
| CVE-2026-47848 | 6.1 MEDIUM | Reactor Netty WebSocket Client Leaks Credentials On Redirect |
| CVE-2026-47857 | 5.9 MEDIUM | Reactor Core windowTimeout fair-backpressure stream hang due to 20-bit index wrap-around |
| CVE-2026-47862 | 5.4 MEDIUM | ZipTransformer uses file_name header to build workDirectory path without sanitization |
| CVE-2026-47859 | 5.4 MEDIUM | Unbounded memory allocation in RFC6587SyslogDeserializer (octet-counted framing) — remote |
| CVE-2026-47844 | 5.3 MEDIUM | Reactor Netty HTTP Server Leaks Exception Details |
| CVE-2026-47845 | 5.3 MEDIUM | Reactor Netty HTTP Server may incorrectly evaluate proxy addresses |
| CVE-2026-47874 | 5.3 MEDIUM | Reactor Netty HTTP Server Denial of Service With Pipelined Requests |
| CVE-2026-47834 | 4.8 MEDIUM | Spring Data JPA Sort expression validation bypass |
| CVE-2026-47850 | 4.3 MEDIUM | Spring Data REST allows mutation of the version property of immutable aggregates via PUT |
| CVE-2026-47843 | 3.7 LOW | Reactor Netty may incorrectly route traffic due to DNS resolver reuse |
IV. Related Vulnerabilities
Same vendor: Spring
-
CVE-2026-47874
Reactor Netty HTTP Server Denial of Service With Pipelined R -
CVE-2026-47861
UDP adapter sends ack to attacker-supplied host:port parsed -
CVE-2026-47862
ZipTransformer uses file_name header to build workDirectory -
CVE-2026-47860
Unbounded decompression of attacker-supplied compressed mess -
CVE-2026-47859
Unbounded memory allocation in RFC6587SyslogDeserializer (oc
V. Comments for CVE-2026-47863
No comments yet