# What is CVE-2020-27174? > CVE-2020-27174 is a high-severity flaw (CVSS 7.5) in Firecracker from Amazon, published on 16 October 2020. 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 1.7%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.edgeprotect.io/what-is/cve-2020-27174 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **EdgeProtect risk score:** 47 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.5 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:** 1.7% (latest exploit-likelihood forecast) - **Published:** 16 October 2020 - **Record last updated:** 21 July 2021 - **Main product:** Firecracker from Amazon - **Affected products:** 1 ## What is CVE-2020-27174? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline. ### The official description In Amazon AWS Firecracker before 0.21.3, and 0.22.x before 0.22.1, the serial console buffer can grow its memory usage without limit when data is sent to the standard input. This can result in a memory leak on the microVM emulation thread, possibly occupying more memory than intended on the host. ### What kind of flaw is it? - CWE-401: Missing Release of Memory after Effective Lifetime ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - 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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` ## Is CVE-2020-27174 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 1.7%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%, 1.7%. ### Timeline - 16 October 2020: Published - 21 July 2021: Record last updated ### How EdgeProtect ranks it CVE-2020-27174 scores **47 out of 100 (Medium)**, with the action "Plan remediation". 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-2020-27174? The published record lists 1 product. Versions are as published: "before 0.21.3" means every version up to, but not including, 0.21.3. - [Firecracker](https://www.edgeprotect.io/product/amazon/firecracker) by [Amazon](https://www.edgeprotect.io/vendors/amazon) (Application): before 0.21.3, 0.22.0 to before 0.22.1 ## How do I fix CVE-2020-27174? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? EdgeProtect 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 advisories and patch notes 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 - [github.com](https://github.com/firecracker-microvm/firecracker/pull/2178) (Patch, Third-party advisory) - [github.com](https://github.com/firecracker-microvm/firecracker/pull/2179) (Patch, Third-party advisory) - [openwall.com](http://www.openwall.com/lists/oss-security/2020/10/23/1) (Third-party advisory) - [github.com](https://github.com/firecracker-microvm/firecracker/issues/2177) (Third-party advisory) ## Questions ### What is CVE-2020-27174? CVE-2020-27174 is a high-severity flaw in Firecracker from Amazon, published on 16 October 2020. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline. ### How serious is CVE-2020-27174? It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2020-27174 is 47 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2020-27174 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 1.7%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2020-27174 affect? For Firecracker from Amazon: before 0.21.3, 0.22.0 to before 0.22.1. ### How do I fix CVE-2020-27174? 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-2020-27174 affect you? EdgeProtect 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.edgeprotect.io/register Book a demo: https://www.edgeprotect.io/contact