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Fencer Vulns
medium 6.1

CVE-2023-20082 json

Cisco IOS XE Software for Cisco Catalyst 9300 Series Switches Secure Boot Bypass Vulnerability

published 2023-03-23 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-24261

cvss
6.1
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 31%
public exploits
0
none known

Summary

A vulnerability in Cisco IOS XE Software for Cisco Catalyst 9300 Series Switches could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to the device to execute persistent code at boot time and break the chain of trust. This vulnerability is due to errors that occur when retrieving the public release key that is used for image signature verification. An attacker could exploit this vulnerability by modifying specific variables in the Serial Peripheral Interface (SPI) flash memory of an affected device. A successful exploit could allow the attacker to execute persistent code on the underlying operating system. Note: In Cisco IOS XE Software releases 16.11.1 and later, the complexity of an attack using this vulnerability is high. However, an attacker with level-15 privileges could easily downgrade the Cisco IOS XE Software on a device to a release that would lower the attack complexity.

Patch / fix

  • cisco ios_xe 17.3.7, 17.6.5

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2 y ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 6.8 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Cisco Cisco IOS XE ROMMON Software

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command
Technology feeds

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.