CVE-2026-41221Intel(R) Slim Bootloader integer overflow
CVE-2026-41221 is a integer overflow in Intel(R) Slim Bootloader, rated high (8.6 on CVSS 4.0).
Why this priority: High severity, with no exploitation signal yet.
Published · Updated · NVD status: Awaiting Analysis
What it is
A calculation wraps around, so a size or count ends up far smaller or larger than intended, often leading to memory corruption.
How it is reached
An attacker can exploit it with physical access to the device, without an account, and nobody has to click anything.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker crash the process, read memory, or in the worst case run code. The damage can spread past the vulnerable component into others.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- No fixed version is listed yet. Find every place Intel(R) Slim Bootloader runs, watch the references for a fix, and plan a replacement if it is no longer supported.
Description from NVD
Integer overflow in the UEFI firmware for the Intel(R) Slim Bootloader within Ring 0: Bare Metal OS may allow an escalation of privilege. Startup code and smm adversary with an unauthenticated user combined with a low complexity attack may enable escalation of privilege. This result may potentially occur via physical access when attack requirements are not present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (high), integrity (high) and availability (high) of the vulnerable system, resulting in subsequent system confidentiality (high), integrity (high) and availability (high) impacts.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Native code: operating systems, browsers and firmware. The flaw sits wherever native code reads untrusted data.
- Network appliances and media or file parsers. The flaw sits wherever native code reads untrusted data.
Trust boundaries in play
- Host boundary. The attacker needs a foothold on the machine first; the flaw turns a small foothold into a bigger one.
- Isolation between components. The impact crosses out of the vulnerable component into others it should be isolated from.
- Wherever native code reads untrusted data. An attacker who crosses it can crash the process, read memory, or in the worst case run code.
Questions to answer about your own systems
- Where does Intel(R) Slim Bootloader run in your systems, and at which version?
- Which of those devices sit where outsiders can touch them?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.