How severe is CVE-2021-34204?

CVE-2021-34204 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-34204 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34204?

CVE-2021-34204 affects Dlink Dir-2640-us Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34204?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-34204 published?

CVE-2021-34204 was published on 2021-06-16 and last updated on 2026-07-05.

CVE-2021-34204

CVE-2021-34204 is a medium-severity vulnerability in Dlink Dir-2640-us Firmware with a CVSS 3.x base score of 6.8. 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-522.

Key facts

Severity: Medium (CVSS 3.x base score 6.8)
CVSS v2: 7.2
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-522
Affected product: Dlink Dir-2640-us Firmware
Published: 2021-06-16
Last modified: 2026-07-05

Description

D-Link DIR-2640-US 1.01B04 is affected by Insufficiently Protected Credentials. D-Link AC2600(DIR-2640) stores the device system account password in plain text. It does not use linux user management. In addition, the passwords of all devices are the same, and they cannot be modified by normal users. An attacker can easily log in to the target router through the serial port and obtain root privileges.

Frequently asked questions

What is CVE-2021-34204?: D-Link DIR-2640-US 1.01B04 is affected by Insufficiently Protected Credentials. D-Link AC2600(DIR-2640) stores the device system account password in plain text. It does not use linux user management. In addition, the passwords of all devices are the same, and they cannot be modified by normal users. An attacker can easily log in to the target router through the serial port and obtain root privileges.
How severe is CVE-2021-34204?: CVE-2021-34204 has a CVSS 3.x base score of 6.8, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-34204 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34204?: CVE-2021-34204 affects Dlink Dir-2640-us Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34204?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-34204 published?: CVE-2021-34204 was published on 2021-06-16 and last updated on 2026-07-05.

References

Affected products (1)

cpe:2.3:o:dlink:dir-2640-us_firmware:1.01b04:*:*:*:*:*:*:*

More vulnerabilities in Dlink Dir-2640-us Firmware

CVE-2021-20132 — High (CVSS 8.8): Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 use default hard-coded credentials, which can…
CVE-2021-20134 — High (CVSS 8.4): Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal…
CVE-2021-34203 — High (CVSS 8.1): D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control. Router ac2600 (dir-2640-us), when setting PPPoE,…
CVE-2021-34202 — High (CVSS 7.8): There are multiple out-of-bounds vulnerabilities in some processes of D-Link AC2600(DIR-2640) 1.01B04. Ordinary…
CVE-2021-34201 — High (CVSS 7.1): D-Link DIR-2640-US 1.01B04 is vulnerable to Buffer Overflow. There are multiple out-of-bounds vulnerabilities in some…
CVE-2021-20133 — Medium (CVSS 6.1): Quagga Services on D-Link DIR-2640 less than or equal to version 1.11B02 are affected by an absolute path traversal…

All CVEs affecting Dlink Dir-2640-us Firmware →

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CVE-2024-51545 — Critical (CVSS 10.0): Username Enumeration vulnerabilities allow access to application level username add, delete, modify and list…
CVE-2023-1778 — Critical (CVSS 10.0): This vulnerability exists in GajShield Data Security Firewall firmware versions prior to v4.28 (except v4.21) due to…

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