Cisco IOS XE Software Secure Boot Bypass Vulnerabilities

TL;DR 📌

Multiple vulnerabilities in Cisco IOS XE Software could allow an authenticated local attacker or an unauthenticated attacker with physical access to execute persistent code at boot time, compromising device security. Cisco has released fixed software, and no workarounds are available.

What happened 🕵️‍♂️

Cisco has identified multiple vulnerabilities in its IOS XE Software that could allow an attacker to bypass secure boot mechanisms. These vulnerabilities stem from improper validation of software packages, enabling an attacker to place a crafted file on an affected device. This could lead to the execution of persistent code on the operating system, effectively breaking the chain of trust.

Affected products 🖥️

The following Cisco products are affected if they are running vulnerable releases of Cisco IOS XE Software:

• 1000 Series Integrated Services Routers (First Affected Release: 17.8.1)
• 1100 Terminal Services Gateways (17.7.1)
• 4000 Series Integrated Services Routers (17.3.1)
• 8100 Series Secure Routers (17.15.1)
• 8400 Series Secure Routers (17.12.1)
• ASR 1000 Series Aggregation Services Routers (17.7.1)
• C8375-E-G2 Platforms (17.15.3)
• Catalyst IE3300 Rugged Series Routers (17.12.1)
• Catalyst IR1100 Rugged Series Routers (17.13.1)
• Catalyst IR8100 Heavy Duty Series Routers (17.4.1)
• Catalyst IR8300 Rugged Series Routers (17.7.1)
• Catalyst 8200 Series Edge Platforms (17.8.1)
• Catalyst 8300 Series Edge Platforms (17.8.1)
• Catalyst 8500L Edge Platforms (17.8.1)
• Catalyst 9200 Series Switches (17.8.1)
• Embedded Services 3300 Series (17.12.1)
• VG410 Analog Voice Gateways (17.17.1)

Fixed software 🔧

Upgrade to the first fixed release in your train (or later):

Workarounds 🧯

There are no workarounds available for these vulnerabilities.

Risk in context 🎯

The highest CVSS score for these vulnerabilities is 6.7, which is classified as Medium severity. The risk is primarily associated with local access or physical access to the device, making it less likely to be exploited remotely. However, the potential for persistent code execution poses a significant security risk.

Fast facts ⚡

• Vulnerabilities allow bypassing secure boot mechanisms.
• Exploitation requires either local authenticated access or physical access.
• No workarounds are available; immediate software updates are necessary.

For leadership 🧭

Executive summary. Routers and switches running affected IOS XE releases can have persistent, boot-level code planted by someone with local admin access or physical access to the device, breaking the assurance that secure boot is meant to provide. There’s no workaround, so remediation depends entirely on scheduling the upgrade to fixed IOS XE software.

Why it matters:

• Affects a wide range of deployed Cisco gear including ISR 1000/4000 series, ASR 1000, multiple Catalyst edge and switch platforms, and IR/IE ruggedised routers, so the exposure spans branch, industrial and edge networks.
• Because the flaw is in package validation, a successful bypass installs code that persists across reboots and undermines the chain of trust secure boot exists to protect - not a transient session compromise.
• No mitigating configuration exists; the only remediation path is upgrading to the first fixed release for each affected train.
• Exploitation needs local authenticated access or physical possession of the device, which narrows likely attackers to insiders, contractors, or anyone who can get hands-on with hardware in branch offices or field cabinets.

Now / Next / Later:

• Now: Identify every device in your estate matching the affected product list and IOS XE release ranges, and tighten physical and administrative access controls on them until patched.
• Next: Schedule upgrades to the first fixed IOS XE release for each affected platform train during your next maintenance window, prioritising devices in less physically secure locations such as branch or field sites.
• Later: Build routine cross-checks between deployed IOS XE versions and Cisco’s fixed-release advisories into your patch management process, and review physical access controls for network hardware as a standing control rather than a one-off response.