What’s Vulnerable › Vulnerabilities
CVE-2021-20844
- Severity: medium (CVSS 5.7 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 1.0% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2021-11-24 · updated 2026-06-17
- Weakness: CWE-116
Description
Improper neutralization of HTTP request headers for scripting syntax vulnerability in the Web GUI of RTX830 Rev.15.02.17 and earlier, NVR510 Rev.15.01.18 and earlier, NVR700W Rev.15.00.19 and earlier, and RTX1210 Rev.14.01.38 and earlier allows a remote authenticated attacker to obtain sensitive information via a specially crafted web page.
Affected products
- Ntt-West Biz Box Nvr510 Firmware: before 15.01.18 — fixed in 15.01.18
- Ntt-West Biz Box Nvr700W Firmware: through 15.00.19
- Ntt-West Biz Box Rtx1210 Firmware: through 14.01.38
- Ntt-West Biz Box Rtx830 Firmware: through 15.02.17
- Yamaha Nvr510 Firmware: through 15.01.18
- Yamaha Nvr700W Firmware: through 15.00.19
- Yamaha Rtx1210 Firmware: through 14.01.38
- Yamaha Rtx830 Firmware: through 15.02.17
How to fix
Upgrade to a fixed version: Ntt-West Biz Box Nvr510 Firmware 15.01.18. Check the vendor advisory for mitigations.
References
- http://www.rtpro.yamaha.co.jp/RT/FAQ/Security/JVNVU91161784.html
- https://business.ntt-east.co.jp/topics/2021/11_09.html
- https://jvn.jp/en/vu/JVNVU91161784/index.html
- https://www.ntt-west.co.jp/smb/kiki_info/info/211109.html
- http://www.rtpro.yamaha.co.jp/RT/FAQ/Security/JVNVU91161784.html
- https://business.ntt-east.co.jp/topics/2021/11_09.html
- https://jvn.jp/en/vu/JVNVU91161784/index.html
- https://www.ntt-west.co.jp/smb/kiki_info/info/211109.html
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