CVE-2026-20104 (GCVE-0-2026-20104)
Vulnerability from cvelistv5
Published
2026-03-25 16:05
Modified
2026-03-26 17:39
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-124 - Buffer Underwrite ('Buffer Underflow')
Summary
A vulnerability in the bootloader of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches, Cisco Catalyst ESS9300 Embedded Series Switches, Cisco Catalyst IE9310 and IE9320 Rugged Series Switches, and Cisco IE3500 and IE3505 Rugged Series Switches could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to an affected device to execute arbitrary code at boot time and break the chain of trust.
This vulnerability is due to insufficient validation of software at boot time. An attacker could exploit this vulnerability by manipulating the loaded binaries on an affected device to bypass some of the integrity checks that are performed during the boot process. A successful exploit could allow the attacker to execute code that bypasses the requirement to run Cisco-signed images.
Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates because this vulnerability allows an attacker to bypass a major security feature of a device.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Cisco | Cisco IOS XE Software |
Version: 16.12.8 Version: 16.12.6 Version: 16.12.6a Version: 16.12.7 Version: 17.3.3 Version: 17.3.4 Version: 17.3.5 Version: 17.3.6 Version: 17.3.4b Version: 17.3.7 Version: 17.3.8 Version: 17.3.8a Version: 17.4.1 Version: 17.5.1 Version: 17.6.1 Version: 17.6.2 Version: 17.6.3 Version: 17.6.1y Version: 17.6.4 Version: 17.6.5 Version: 17.6.6 Version: 17.6.6a Version: 17.6.5a Version: 17.6.7 Version: 17.6.8 Version: 17.7.1 Version: 17.7.1a Version: 17.10.1 Version: 17.8.1 Version: 17.8.1a Version: 17.9.1 Version: 17.9.2 Version: 17.9.1a Version: 17.9.3 Version: 17.9.4 Version: 17.9.5 Version: 17.9.4a Version: 17.9.5b Version: 17.9.6 Version: 17.9.6a Version: 17.9.7 Version: 17.9.8 Version: 17.11.1 Version: 17.12.1 Version: 17.12.2 Version: 17.12.3 Version: 17.12.4 Version: 17.12.5 Version: 17.12.6 Version: 17.13.1 Version: 17.14.1 Version: 17.15.1 Version: 17.15.2 Version: 17.15.3 Version: 17.15.4 Version: 17.16.1 Version: 17.17.1 Version: 17.18.1 Version: 17.18.2 |
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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