EUVD-2026-45016Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Unauthenticated network-reachable endpoint (AV:N/PR:N/UI:N) with a simple crafted frame (AC:L); impact is pure availability exhaustion (A:H) with no confidentiality or integrity effect.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4DescriptionCVE.org
Centrifugo is an open-source scalable real-time messaging server. Prior to 6.8.4, Centrifugo unidirectional WebSocket transport with uni_websocket.compression enabled enforced uni_websocket.message_size_limit against compressed wire-frame length in internal/websocket/conn.go advanceFrame, but ReadMessage used io.ReadAll after decompression without an output cap, allowing unauthenticated requests to /connection/uni_websocket to trigger large memory and CPU consumption. This issue is fixed in version 6.8.4.
AnalysisAI
Uncontrolled memory and CPU exhaustion in Centrifugo real-time messaging server before 6.8.4 lets unauthenticated attackers send a small compressed WebSocket frame to the unidirectional transport that inflates into a massive decompressed payload. The message_size_limit was only checked against compressed wire bytes, while decompressed output was read via io.ReadAll with no cap, enabling a classic decompression bomb denial of service. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target run the unidirectional WebSocket transport with uni_websocket.compression explicitly enabled - this is the exact precondition named in the description, and instances with compression disabled are not affected. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H) scores 8.7 and is internally consistent with the description: network-reachable, low complexity, unauthenticated, with a pure availability impact and no confidentiality or integrity loss. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An unauthenticated attacker who can reach a Centrifugo instance's /connection/uni_websocket endpoint negotiates permessage-deflate compression and sends a highly compressible frame (e.g. a few kilobytes of repeated bytes) that stays under message_size_limit on the wire. … |
| Remediation | Vendor-released patch: upgrade to Centrifugo 6.8.4 (https://github.com/centrifugal/centrifugo/releases/tag/v6.8.4), which adds a decompressed_message_size_limit cap for the WebSocket and uni_websocket transports; per the advisory GHSA-q6mr-3g59-5m8x and PR https://github.com/centrifugal/centrifugo/pull/1162 (commit 46d40e4ac3a5446c9745f8b219197166ae12a6e5) the limit defaults to message_size_limit times 10 when left at zero. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all Centrifugo deployments and verify which versions are in use, particularly any running before version 6.8.4. …
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