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CVE-2021-20134

30
FAUCET Score

CVE-2021-20134 describes an absolute path traversal vulnerability in Quagga Services on D-Link DIR-2640 routers running firmware version 1.11B02 or earlier. A remote, authenticated attacker can exploit this flaw to set an arbitrary file as a log file, enabling the appending of data to it. This vulnerability carries a CVSS score of 8.4 (High), indicating a high-impact attack that can lead to remote code execution and an unauthenticated root shell on the device. Despite its severity, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.11b02CPE matchmatch criteria
cpe:2.3:o:dlink:dir-2640-us_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.4HIGH

CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.7
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
7.53%
Probability of exploitation in next 30 days
EPSS Percentile
93.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0753 is in the 98th percentile among its peer group of 49 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.2 Bluesky, 0.0 Mastodon, and 0.0 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (5)

asteriskvendor investigatingvia llm_extracted
ciscovendor investigatingvia llm_extracted
miniovendor investigatingvia llm_extracted
opensshvendor investigatingvia llm_extracted
railsvendor investigatingvia llm_extracted

Vendor Advisories (5)

opensshllm-openssh-87dcea0097525c99HIGH

Critical Vulnerabilities on the D-Link DIR-2640 Router

Oct 19, 2021
railsllm-rails-486cd415774a802cHIGH

Critical Vulnerabilities on the D-Link DIR-2640 Router

Oct 19, 2021
miniollm-minio-16563aa65dea5f34HIGH

Critical Vulnerabilities on the D-Link DIR-2640 Router

Oct 19, 2021
ciscollm-cisco-48484d23210b67fcHIGH

Critical Vulnerabilities on the D-Link DIR-2640 Router

Oct 19, 2021
asteriskllm-asterisk-3258a40a5f11dd6eHIGH

Critical Vulnerabilities on the D-Link DIR-2640 Router

Oct 19, 2021

References

tenable.com / security/research/tra-2021-44
ExploitThird Party Advisory