CVE-2020-3284
Cisco IOS XR Software Enhanced Preboot eXecution Environment Unsigned Code Execution Vulnerability
A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Cisco IOS XR Software Enhanced Preboot eXecution Environment Unsigned Code Execution Vulnerability
A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory.
- Record
CVE-2020-3284- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-284
- Updated
- 2026-11-02
EUVDEUVD-2020-24555
A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory.
- Record
EUVD-2020-24555- CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-5xjq-f58j-4hph No score
A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR...
A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory.
- Record
GHSA-5xjq-f58j-4hph- Updated
- 2026-11-02
NVD
A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory.
- Record
CVE-2020-3284- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.0
- 8.1 High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 9.3 High
AV:N/AC:M/Au:N/C:C/I:C/A:C - Weakness
- CWE-284
- Updated
- 2026-11-02
Affected products
- cisco ios xr software
- cisco ios xr
- cisco a99-rp2-se firmware
- cisco a99-rp2-tr firmware
- cisco a99-rp3-se firmware
- cisco a99-rp3-tr firmware
- cisco a99-rsp-se firmware
- cisco a99-rsp-tr firmware
- cisco a9k-rsp5-se firmware
- cisco a9k-rsp5-tr firmware
- cisco a9k-rsp880-lt-se firmware
- cisco a9k-rsp880-lt-tr firmware
Show 33 moreShow less
- cisco a9k-rsp880-se firmware
- cisco a9k-rsp880-tr firmware
- cisco asr-9901-rp firmware
- cisco n540-12z20g-sys-a\/d firmware
- cisco n540-24z8q2c-m firmware
- cisco n540-28z4c-sys-a\/d firmware
- cisco n540-acc-sys firmware
- cisco n540x-12z16g-sys-a\/d firmware
- cisco n540x-16z4g8q2c-a\/d firmware
- cisco n560-4-sys firmware
- cisco n560-7-sys firmware
- cisco nc55-rp-e firmware
- cisco nc55-rp firmware
- cisco ncs-5501-se firmware
- cisco ncs-5501 firmware
- cisco ncs-5502-se firmware
- cisco ncs-5502 firmware
- cisco ncs-55a1-24h firmware
- cisco ncs-55a1-24q6h-s firmware
- cisco ncs-55a1-36h-s firmware
- cisco ncs-55a1-36h-se-s firmware
- cisco ncs-55a2-mod-hd-s firmware
- cisco ncs-55a2-mod-hx-s firmware
- cisco ncs-55a2-mod-s firmware
- cisco ncs-55a2-mod-se-h-s firmware
- cisco ncs-55a2-mod-se-s firmware
- cisco ncs1001 firmware
- cisco ncs1002 firmware
- cisco ncs1004 firmware
- cisco ncs5001 firmware
- cisco ncs5002 firmware
- cisco ncs5011 firmware
- cisco ncs55-a1-48q6h firmware
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | ||
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-3284 is a high vulnerability (CVSS 8.1) in Cisco Ios Xr Software, published November 6, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.89%, the 87th percentile. No source names a fixed version.