Cisco Secure Boot Hardware Tampering Vulnerability
Description
A vulnerability in the logic that handles access control to one of the hardware components in Cisco's proprietary Secure Boot implementation could allow an authenticated, local attacker to write a modified firmware image to the component. This vulnerability affects multiple Cisco products that support hardware-based Secure Boot functionality. The vulnerability is due to an improper check on the area of code that manages on-premise updates to a Field Programmable Gate Array (FPGA) part of the Secure Boot hardware implementation. An attacker with elevated privileges and access to the underlying operating system that is running on the affected device could exploit this vulnerability by writing a modified firmware image to the FPGA. A successful exploit could either cause the device to become unusable (and require a hardware replacement) or allow tampering with the Secure Boot verification process, which under some circumstances may allow the attacker to install and boot a malicious software image. An attacker will need to fulfill all the following conditions to attempt to exploit this vulnerability: Have privileged administrative access to the device. Be able to access the underlying operating system running on the device; this can be achieved either by using a supported, documented mechanism or by exploiting another vulnerability that would provide an attacker with such access. Develop or have access to a platform-specific exploit. An attacker attempting to exploit this vulnerability across multiple affected platforms would need to research each one of those platforms and then develop a platform-specific exploit. Although the research process could be reused across different platforms, an exploit developed for a given hardware platform is unlikely to work on a different hardware platform.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Cisco Secure Boot hardware tampering vulnerability allows authenticated local attacker to write modified firmware to FPGA, potentially bypassing Secure Boot and enabling malicious software installation.
Vulnerability
A logic flaw in the access control handling of Cisco's proprietary Secure Boot implementation allows an authenticated, local attacker to write a modified firmware image to the Field Programmable Gate Array (FPGA) component. The vulnerability stems from an improper check in the code that manages on-premise updates to the FPGA. Affected products include multiple Cisco devices such as the ASA 5500-X series (e.g., ASA 5506-X, ASA 5508-X, ASA 5516-X) and the Firepower 2100 Series, as well as the Rockwell Automation Allen-Bradley Stratix 5950 Security Appliance (models 1783-SAD4T0SBK9, 1783-SAD4T0SPK9, 1783-SAD2T2SBK9, 1783-SAD2T2SPK9) [1][2].
Exploitation
To exploit this vulnerability, an attacker must have privileged administrative access to the device and be able to access the underlying operating system—either through a supported, documented mechanism or by exploiting another vulnerability. The attacker must also develop or obtain a platform-specific exploit; while research may be reused across platforms, an exploit for one hardware platform is unlikely to work on another [1]. The attack sequence involves writing a crafted firmware image to the FPGA, bypassing the intended access controls [3].
Impact
A successful exploit can render the device unusable, requiring hardware replacement, or allow tampering with the Secure Boot verification process. Under certain circumstances, this may enable the attacker to install and boot a malicious software image, compromising the integrity of the boot chain and potentially leading to persistent unauthorized access [1][2]. The CVSS v3 base score is 6.7 (AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H) [2].
Mitigation
Cisco has released firmware updates for affected products; for example, the ASA 5500-X series fixed in firmware release 1.1.15 (image asa5500-firmware-1115.SPA) [1]. Rockwell Automation recommends updating the Stratix 5950 to firmware version FRN v6.4.0 [2]. No workarounds are documented; users should apply the appropriate fixed release as soon as possible. The CERT/CC note does not provide additional mitigation details [3].
AI Insight generated on May 25, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
2- Range: unspecified
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190513-securebootmitrevendor-advisoryx_refsource_CISCO
- www.kb.cert.org/vuls/id/400865mitrethird-party-advisoryx_refsource_CERT-VN
- www.securityfocus.com/bid/108350mitrevdb-entryx_refsource_BID
- www.us-cert.gov/ics/advisories/icsa-20-072-03mitrex_refsource_MISC
News mentions
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