CVE-2023-50923Network attack vector

Covert data transfer via disabled spin bit

Published Feb 20, 2024 · Updated Dec 4, 2024

Covert channel exposure in QUIC allows remote attackers to encode data as latency spin-bit changes after the feature is disabled. RFC 9000 permits a disabled endpoint to set the bit to any value, enabling a controlled endpoint to modulate the visible bit across 1-RTT packets. Exploitation requires control of an established QUIC endpoint, and the CVE claim is disputed with no affected implementation or version identified.

CVSS severity4.3
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Covert channel exposure in QUIC allows remote attackers to encode data as latency spin-bit changes after the feature is disabled. RFC 9000 permits a disabled endpoint to set the bit to any value, enabling a controlled endpoint to modulate the visible bit across 1-RTT packets. Exploitation requires control of an established QUIC endpoint, and the CVE claim is disputed with no affected implementation or version identified.

The record

CVE
CVE-2023-50923
Published
Feb 20, 2024
Updated
Dec 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-352, T1048
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Feb 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Dec 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
T1048Exfiltration Over Alternative Protocol

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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