# What is CVE-2021-33155? > CVE-2021-33155 is a medium-severity flaw (CVSS 5.7) in Ax211 Firmware from Intel, published on 9 February 2022. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 0.5%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-33155 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 18 out of 100 (Info); action: Track. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.7 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 0.5% (latest exploit-likelihood forecast) - **Published:** 9 February 2022 - **Record last updated:** 5 May 2025 - **Main product:** Ax211 Firmware from Intel - **Affected products:** 32 ## What is CVE-2021-33155? In plain terms An attacker has to be on the same local network with an ordinary user account, and nobody has to click anything. If it works, the attacker can take it offline. ### The official description Improper input validation in firmware for some Intel(R) Wireless Bluetooth(R) and Killer(TM) Bluetooth(R) products before version 22.100 may allow an authenticated user to potentially enable denial of service via adjacent access. ### What kind of flaw is it? - CWE-20: Improper Input Validation ### How an attack on it works - Where an attacker can be: On the same local network - How hard it is to pull off: Easy: no special conditions - Login needed first: An ordinary user account - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can take it offline Severity vector: `CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` ## Is CVE-2021-33155 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.5%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 0.5%, 0.5%, 0.5%, 0.5%, 0.5%, 0.5%, 0.5%. ### Timeline - 9 February 2022: Published - 5 May 2025: Record last updated ### How Precursor Intelligence ranks it CVE-2021-33155 scores **18 out of 100 (Info)**, with the action "Track". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: key context - Real threat activity around it: key context 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2021-33155? The published record lists 32 products. Versions are as published: "before 22.100" means every version up to, but not including, 22.100. - [Ax211 Firmware](https://www.precursorintelligence.com/product/intel/ax211_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 1550](https://www.precursorintelligence.com/product/intel/ac_1550) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 1550 Firmware](https://www.precursorintelligence.com/product/intel/ac_1550_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 3165](https://www.precursorintelligence.com/product/intel/ac_3165) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 3165 Firmware](https://www.precursorintelligence.com/product/intel/ac_3165_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 7265](https://www.precursorintelligence.com/product/intel/ac_7265) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 7265 Firmware](https://www.precursorintelligence.com/product/intel/ac_7265_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 8260](https://www.precursorintelligence.com/product/intel/ac_8260) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 8260 Firmware](https://www.precursorintelligence.com/product/intel/ac_8260_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 8265](https://www.precursorintelligence.com/product/intel/ac_8265) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 8265 Firmware](https://www.precursorintelligence.com/product/intel/ac_8265_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 9260](https://www.precursorintelligence.com/product/intel/ac_9260) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 9260 Firmware](https://www.precursorintelligence.com/product/intel/ac_9260_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 9461](https://www.precursorintelligence.com/product/intel/ac_9461) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 9461 Firmware](https://www.precursorintelligence.com/product/intel/ac_9461_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 9462](https://www.precursorintelligence.com/product/intel/ac_9462) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 9462 Firmware](https://www.precursorintelligence.com/product/intel/ac_9462_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac 9560](https://www.precursorintelligence.com/product/intel/ac_9560) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac 9560 Firmware](https://www.precursorintelligence.com/product/intel/ac_9560_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ac3168](https://www.precursorintelligence.com/product/intel/ac3168) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ac3168 Firmware](https://www.precursorintelligence.com/product/intel/ac3168_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ax1650](https://www.precursorintelligence.com/product/intel/ax1650) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ax1650 Firmware](https://www.precursorintelligence.com/product/intel/ax1650_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ax1675](https://www.precursorintelligence.com/product/intel/ax1675) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ax1675 Firmware](https://www.precursorintelligence.com/product/intel/ax1675_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ax200](https://www.precursorintelligence.com/product/intel/ax200) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ax200 Firmware](https://www.precursorintelligence.com/product/intel/ax200_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ax201](https://www.precursorintelligence.com/product/intel/ax201) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ax201 Firmware](https://www.precursorintelligence.com/product/intel/ax201_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ax210](https://www.precursorintelligence.com/product/intel/ax210) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified - [Ax210 Firmware](https://www.precursorintelligence.com/product/intel/ax210_firmware) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Operating system): before 22.100 - [Ax211](https://www.precursorintelligence.com/product/intel/ax211) by [Intel](https://www.precursorintelligence.com/vendors/intel) (Hardware): version not specified ## How do I fix CVE-2021-33155? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [intel.com](https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00604.html) (Vendor advisory) ## Questions ### What is CVE-2021-33155? CVE-2021-33155 is a medium-severity flaw in Ax211 Firmware from Intel, published on 9 February 2022. An attacker has to be on the same local network with an ordinary user account, and nobody has to click anything. If it works, the attacker can take it offline. ### How serious is CVE-2021-33155? It scores 5.7 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2021-33155 is 18 out of 100, which is Info. Its action is "Track". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2021-33155 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.5%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2021-33155 affect? For Ax211 Firmware from Intel: before 22.100. The record lists 32 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2021-33155? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2021-33155 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact