# What is CVE-2021-20680? > CVE-2021-20680 is a medium-severity flaw (CVSS 6.1) in Aterm Wg1900hp2 Firmware from Nec, published on 26 April 2021. 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 0.8%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-20680 ## 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:** 23 out of 100 (Low); action: Monitor. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 6.1 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:** 0.8% (latest exploit-likelihood forecast) - **Published:** 26 April 2021 - **Record last updated:** 5 May 2021 - **Main product:** Aterm Wg1900hp2 Firmware from Nec - **Affected products:** 34 ## What is CVE-2021-20680? In plain terms It can be attacked from anywhere on the internet without logging in, but a person has to take an action first. If it works, the attacker can read some data and change some data. ### The official description Cross-site scripting vulnerability in NEC Aterm devices (Aterm WG1900HP2 firmware Ver.1.3.1 and earlier, Aterm WG1900HP firmware Ver.2.5.1 and earlier, Aterm WG1800HP4 firmware Ver.1.3.1 and earlier, Aterm WG1800HP3 firmware Ver.1.5.1 and earlier, Aterm WG1200HS2 firmware Ver.2.5.0 and earlier, Aterm WG1200HP3 firmware Ver.1.3.1 and earlier, Aterm WG1200HP2 firmware Ver.2.5.0 and earlier, Aterm W1200EX firmware Ver.1.3.1 and earlier, Aterm W1200EX-MS firmware Ver.1.3.1 and earlier, Aterm WG1200HS firmware all versions Aterm WG1200HP firmware all versions Aterm WF800HP firmware all versions Aterm WF300HP2 firmware all versions Aterm WR8165N firmware all versions Aterm W500P firmware all versions, and Aterm W300P firmware all versions) allows remote attackers to inject arbitrary script or HTML via unspecified vectors. ### What kind of flaw is it? - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') ### 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: Yes, a person has to take an action - What an attacker gets: Can read some data and change some data Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N` ## Is CVE-2021-20680 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 0.8%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 0.8%, 0.8%, 0.8%, 0.8%, 0.8%, 0.8%, 0.8%. ### Timeline - 26 April 2021: Published - 5 May 2021: Record last updated ### How Precursor Intelligence ranks it CVE-2021-20680 scores **23 out of 100 (Low)**, with the action "Monitor". 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: smaller factor - Threat activity around it: smaller factor 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-2021-20680? The published record lists 34 products. - [Aterm Wg1900hp2 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1900hp2_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.3.1 - [Aterm W1200ex](https://www.precursorintelligence.com/product/nec/aterm_w1200ex) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm W1200ex Firmware](https://www.precursorintelligence.com/product/nec/aterm_w1200ex_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.3.1 - [Aterm W1200ex-Ms](https://www.precursorintelligence.com/product/nec/aterm_w1200ex-ms) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm W1200ex-Ms Firmware](https://www.precursorintelligence.com/product/nec/aterm_w1200ex-ms_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.3.1 - [Aterm W300p](https://www.precursorintelligence.com/product/nec/aterm_w300p) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm W300p Firmware](https://www.precursorintelligence.com/product/nec/aterm_w300p_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions - [Aterm W500p](https://www.precursorintelligence.com/product/nec/aterm_w500p) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm W500p Firmware](https://www.precursorintelligence.com/product/nec/aterm_w500p_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions - [Aterm Wf300hp2](https://www.precursorintelligence.com/product/nec/aterm_wf300hp2) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wf300hp2 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wf300hp2_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions - [Aterm Wf800hp](https://www.precursorintelligence.com/product/nec/aterm_wf800hp) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wf800hp Firmware](https://www.precursorintelligence.com/product/nec/aterm_wf800hp_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions - [Aterm Wg1200hp](https://www.precursorintelligence.com/product/nec/aterm_wg1200hp) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1200hp Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1200hp_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions - [Aterm Wg1200hp2](https://www.precursorintelligence.com/product/nec/aterm_wg1200hp2) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1200hp2 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1200hp2_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 2.5.0 - [Aterm Wg1200hp3](https://www.precursorintelligence.com/product/nec/aterm_wg1200hp3) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1200hp3 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1200hp3_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.3.1 - [Aterm Wg1200hs](https://www.precursorintelligence.com/product/nec/aterm_wg1200hs) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1200hs Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1200hs_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions - [Aterm Wg1200hs2](https://www.precursorintelligence.com/product/nec/aterm_wg1200hs2) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1200hs2 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1200hs2_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 2.5.0 - [Aterm Wg1200hs3](https://www.precursorintelligence.com/product/nec/aterm_wg1200hs3) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1200hs3 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1200hs3_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.1.2 - [Aterm Wg1800hp3](https://www.precursorintelligence.com/product/nec/aterm_wg1800hp3) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1800hp3 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1800hp3_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.5.1 - [Aterm Wg1800hp4](https://www.precursorintelligence.com/product/nec/aterm_wg1800hp4) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1800hp4 Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1800hp4_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 1.3.1 - [Aterm Wg1900hp](https://www.precursorintelligence.com/product/nec/aterm_wg1900hp) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wg1900hp Firmware](https://www.precursorintelligence.com/product/nec/aterm_wg1900hp_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): up to 2.5.1 - [Aterm Wg1900hp2](https://www.precursorintelligence.com/product/nec/aterm_wg1900hp2) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wr8165n](https://www.precursorintelligence.com/product/nec/aterm_wr8165n) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Hardware): version not specified - [Aterm Wr8165n Firmware](https://www.precursorintelligence.com/product/nec/aterm_wr8165n_firmware) by [Nec](https://www.precursorintelligence.com/vendors/nec) (Operating system): all versions ## How do I fix CVE-2021-20680? 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 - [jpn.nec.com](https://jpn.nec.com/security-info/secinfo/nv21-008.html) (Vendor advisory) - [jvn.jp](https://jvn.jp/en/jp/JVN67456944/index.html) (Third-party advisory) ## Questions ### What is CVE-2021-20680? CVE-2021-20680 is a medium-severity flaw in Aterm Wg1900hp2 Firmware from Nec, published on 26 April 2021. It can be attacked from anywhere on the internet without logging in, but a person has to take an action first. If it works, the attacker can read some data and change some data. ### How serious is CVE-2021-20680? It scores 6.1 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2021-20680 is 23 out of 100, which is Low. Its action is "Monitor". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2021-20680 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 0.8%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2021-20680 affect? For Aterm Wg1900hp2 Firmware from Nec: up to 1.3.1. The record lists 34 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2021-20680? 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-2021-20680 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