Vulnerability · Published Aug 26, 2026 · Assigned by vmware
CVE-2026-47863Reactor Core bufferTimeout fair-backpressure pipeline permanently hangs when upstream delivers items during an active flush
Medium 5.9
In plain English
A medium-severity infinite loop in Reactor Core from Spring. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities).
Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.4%top 65.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Spring | Reactor Core | 3.8.0 – through 3.8.60 – through 3.7.19 |
Weakness: CWE-835 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H