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Fencer Vulns
medium 5.8

CVE-2024-20263 json

A vulnerability with the access control list (ACL) management within a stacked switch configuration of Cisco Business 250 Series Smart Swit…

published 2024-01-26 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-17978

cvss
5.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

A vulnerability with the access control list (ACL) management within a stacked switch configuration of Cisco Business 250 Series Smart Switches and Business 350 Series Managed Switches could allow an unauthenticated, remote attacker to bypass protection offered by a configured ACL on an affected device. This vulnerability is due to incorrect processing of ACLs on a stacked configuration when either the primary or backup switches experience a full stack reload or power cycle. An attacker could exploit this vulnerability by sending crafted traffic through an affected device. A successful exploit could allow the attacker to bypass configured ACLs, causing traffic to be dropped or forwarded in an unexpected manner. The attacker does not have control over the conditions that result in the device being in the vulnerable state. Note: In the vulnerable state, the ACL would be correctly applied on the primary devices but could be incorrectly applied to the backup devices.

Patch / fix

  • cisco cbs250-8t-d_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-8pp-d_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-8t-e-2g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-8pp-e-2g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-8p-e-2g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-8fp-e-2g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-16t-2g_firmware 3.4.0.17
  • cisco cbs250-16p-2g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24t-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24pp-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24p-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24fp-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-48t-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-48pp-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-48p-4g_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24t-4x_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24p-4x_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-24fp-4x_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-48t-4x_firmware 2.5.9.54, 3.4.0.17
  • cisco cbs250-48p-4x_firmware 2.5.9.54, 3.4.0.17

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
NVD 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:L

Affected products

  • Cisco Cisco Small Business Smart and Managed Switches

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.