CVE-2021-20133

CVE-2021-20133 is a medium-severity vulnerability in Dlink Dir-2640-us Firmware with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Description

Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set the "message of the day" banner to any file on the system, allowing them to read all or some of the contents of those files. Such sensitive information as hashed credentials, hardcoded plaintext passwords for other services, configuration files, and private keys can be disclosed in this fashion. Improper handling of filenames that identify virtual resources, such as "/dev/urandom" allows an attacker to effect a denial of service attack against the command line interfaces of the Quagga services (zebra and ripd).

Frequently asked questions

What is CVE-2021-20133?
Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal vulnerability that allows a remote, authenticated attacker to set the "message of the day" banner to any file on the system, allowing them to read all or some of the contents of those files. Such sensitive information as hashed credentials, hardcoded plaintext passwords for other services, configuration files, and private keys can be disclosed in this fashion. Improper handling of filenames that identify virtual resources, such as "/dev/urandom" allows an attacker to effect a denial of service attack against the command line interfaces of the Quagga services (zebra and ripd).
How severe is CVE-2021-20133?
CVE-2021-20133 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2021-20133 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20133?
CVE-2021-20133 affects Dlink Dir-2640-us Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20133?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-20133 published?
CVE-2021-20133 was published on 2021-12-30 and last updated on 2026-06-17.

References

Affected products (1)

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