Known exploited vulnerability
CVE-2021-20090
The short answer
CVE-2021-20090 affects n/a Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3 and is rated critical (CVSS 9.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03: attackers are using it, so patch it first.
What it is
A path traversal vulnerability in the web interfaces of Buffalo WSR-2533DHPL2 firmware version <= 1.02 and WSR-2533DHP3 firmware version <= 1.24 could allow unauthenticated remote attackers to bypass authentication.
Weakness: CWE-22.
Severity
9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploited (CISA KEV)
Yes, since Nov 3, 2021
Federal due date Nov 17, 2021
EPSS, next 30 days
100%
Higher than 100% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
What CISA says to do
Apply updates per vendor instructions.
Affected products
Buffalo WSR-2533DHPL2, Buffalo WSR-2533DHP3. NVD's record lists the exact affected versions.
References
- www.kb.cert.org/vuls/id/914124 Third Party AdvisoryUS Government Resource
- www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/ ExploitThird Party Advisory
- www.tenable.com/security/research/tra-2021-13 ExploitThird Party Advisory
- www.kb.cert.org/vuls/id/914124 Third Party AdvisoryUS Government Resource
- www.secpod.com/blog/arcadyan-based-routers-and-modems-under-active-exploitation/ ExploitThird Party Advisory
- www.tenable.com/security/research/tra-2021-13 ExploitThird Party Advisory
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20090 US Government Resource
Questions
Is CVE-2021-20090 being exploited?
Yes. CISA added CVE-2021-20090 to its Known Exploited Vulnerabilities catalog on 2021-11-03, with a federal remediation due date of 2021-11-17.
How do I fix CVE-2021-20090?
CISA's required action: Apply updates per vendor instructions.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.
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