Integer overflow in the UEFI firmware for the Intel(R) Slim Bootloader within Ring 0: Bare Metal OS may allow an escalation of privilege.
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects Intel Slim Bootloader UEFI firmware running within Ring 0 on a bare metal OS.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 19/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
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.
Who should check
Teams running Intel Slim Bootloader UEFI firmware on listed Intel processors, such as Alder Lake, Raptor Lake, Tiger Lake and Meteor Lake platforms.
Read the source excerpt
“Intel recommends updating Intel® Slim Bootloader to hash 9e77d9abb867e7ab4fec8249035cf9ba6550aed7”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure5/25Specific setups only
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.6/10CVSS 8.6
- No patch5/5No patch listed yet
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 29 if CISA's SSVC rates it automatable
What to do
Check whether your setup matches what the bug needs.
Affects Intel Slim Bootloader UEFI firmware running within Ring 0 on a bare metal OS.Workaround: The checked facts give no workaround. Until a fix is available, follow the guidance in Intel's advisory for the affected firmware.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-41221 (Integer overflow in the UEFI firmware for the Intel(R) Slim Bootloader within Ring 0: Bare Metal OS may allow an escalation of privilege.), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-41221 (entry last updated 2026-11-10): Affected: - n/a Intel(R) Slim Bootloader: version range not reported Fixed versions: none listed yet. Conditions (all must be true for the bug to be hit): - Affects Intel Slim Bootloader UEFI firmware running within Ring 0 on a bare metal OS. (source: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html) Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: physical access, no login, no user action. CISA KEV: CVE-2026-41221 is not listed as of cve.now's last read. This KEV status is for CVE-2026-41221 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html - https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01526.html Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-41221 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-41221.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- n/a Intel(R) Slim Bootloader
Version range not reported
Evidence 3
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Link
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-41221
Is CVE-2026-41221 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
An integer overflow in the UEFI firmware of Intel Slim Bootloader, running in Ring 0 on a bare metal OS, may allow an attacker to escalate privileges.Source: intel.com
Am I affected, and how do I check?
The checked facts cover Intel Slim Bootloader UEFI firmware running within Ring 0 on a bare metal OS, but list no specific versions. To check a system, look up the Slim Bootloader firmware version and compare it with the versions named in Intel's advisory.Source: intel.com
How do I fix CVE-2026-41221?
The checked facts name no fixed version, so no specific upgrade target can be given. Check Intel's advisory for firmware updates for the affected platform.Source: intel.com
What if there's no patch?
The checked facts give no workaround. Until a fix is available, follow the guidance in Intel's advisory for the affected firmware.Source: intel.com