CVE-2024-20465Network attack vector

Unauthenticated ACL bypass via incorrect REP transition handling

Published Sep 25, 2024 · Updated Sep 25, 2024

Access control bypass in Cisco IOS 15.2(8)E2 and later allows remote attackers to send traffic through configured IPv4 ACLs. ACL programming mishandles IPv4 ACLs bound to switched virtual interfaces after an administrator enables and disables REP. Exploitation requires an affected Industrial Ethernet switch with an IPv4 ACL on an SVI and a REP state transition, and it permits traffic that the ACL should block.

CVSS severity5.8
Medium
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access control bypass in Cisco IOS 15.2(8)E2 and later allows remote attackers to send traffic through configured IPv4 ACLs. ACL programming mishandles IPv4 ACLs bound to switched virtual interfaces after an administrator enables and disables REP. Exploitation requires an affected Industrial Ethernet switch with an IPv4 ACL on an SVI and a REP state transition, and it permits traffic that the ACL should block.

The record

CVE
CVE-2024-20465
Published
Sep 25, 2024
Updated
Sep 25, 2024
Vendor
ClamAV
Product
Cisco IOS
Classifications
CWE-284, T1687
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 25, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=15.2\(8\)e2
  2. Affected versionversion=15.2(8)E2
  3. Affected versionversion=15.2\(8\)e3
  4. Affected versionversion=15.2(8)E3
  5. Affected versionversion=15.2\(8\)e4
  6. Affected versionversion=15.2(8)E4
  7. Affected versionversion=15.2\(8\)e5
  8. Affected versionversion=15.2(8)E5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IOSversion=15.2\(8\)e2; version=15.2(8)E2; version=15.2\(8\)e3; version=15.2(8)E3; version=15.2\(8\)e4; version=15.2(8)E4; version=15.2\(8\)e5; version=15.2(8)E5

Published CVSS scores

5.8Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X

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

Weakness, pattern, technique

CWE-284Improper Access Control
T1687Exploitation for Defense Impairment

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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