CVE-2023-20123

Device access via replayed offline MFA codes

Published Apr 5, 2023 · Updated Oct 28, 2024

Authentication bypass in Cisco Duo offline access allows physically proximate attackers to gain unauthorized macOS or Windows device access. The offline credential cache does not expire session credentials, leaving previously used MFA codes valid for replay during local logon. The attacker needs physical access to a device with offline access enabled and a captured valid code; replay grants that user's local access.

CVSS severity6.3
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Cisco Duo offline access allows physically proximate attackers to gain unauthorized macOS or Windows device access. The offline credential cache does not expire session credentials, leaving previously used MFA codes valid for replay during local logon. The attacker needs physical access to a device with offline access enabled and a captured valid code; replay grants that user's local access.

The record

CVE
CVE-2023-20123
Published
Apr 5, 2023
Updated
Oct 28, 2024
Vendor
ClamAV
Product
Cisco Duo
Classifications
CWE-294, T1078
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Duoversion=n/a

Published CVSS scores

6.3Cisco Systems, Inc.CVSS:3.1/AV:P/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
6.5NISTCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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