CVE-2021-34203

HIGHNVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 8.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control. Router ac2600 (dir-2640-us), when setting PPPoE, will start quagga process in the way of whole network monitoring, and this function uses the original default password and port. An attacker can easily use telnet to log in, modify routing information, monitor the traffic of all devices under the router, hijack DNS and phishing attacks. In addition, this interface is likely to be questioned by customers as a backdoor, because the interface should not be exposed.

CVSS v3
8.1
EG Score
8.1(medium)
EPSS
65.0%
KEV
Not listed

Published

June 16, 2021

Last Modified

July 9, 2026

Advisory Details (3)

Auto-updated Jul 5, 2026
No patch confirmed yet.
generic

Security Bulletin | D-Link

https://www.dlink.com/en/security-bulletin/
generic

CVE/2021/CVE-2021-34203 at main · secnotes/CVE · GitHub

https://github.com/liyansong2018/CVE/tree/main/2021/CVE-2021-34203
generic

D-Link

http://d-link.com

Vendor Advisories for CVE-2021-34203(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-12 05:44 UTCEPSS rescore
  2. 2026-07-12 05:44 UTCEPSS rescore
  3. 2026-07-11 08:25 UTCEPSS rescore
  4. 2026-07-11 08:25 UTCEPSS rescore
  5. 2026-07-09 19:07 UTCEPSS rescore
  6. 2026-07-09 02:55 UTCNVD updateCVSS v3 → 8.1 · severity → HIGH
  7. 2026-07-09 01:31 UTCMITRE cvelistV5
  8. 2026-07-08 15:12 UTCEPSS rescore
  9. 2026-07-07 13:43 UTCEPSS rescore
  10. 2026-07-06 16:25 UTCEPSS rescore
  11. 2026-07-06 02:21 UTCEPSS rescore
  12. 2026-07-05 17:59 UTCNVD updateCVSS v3 → 8.1 · severity → HIGH
  13. 2026-07-05 16:09 UTCMITRE cvelistV5
  14. 2026-07-05 02:28 UTCEPSS rescore
  15. 2026-07-05 02:28 UTCEPSS rescore
  16. 2026-07-05 00:28 UTCNVD updateCVSS v3 → 8.1 · severity → HIGH
  17. 2026-07-04 23:57 UTCMITRE cvelistV5
  18. 2026-07-04 06:29 UTCEPSS rescore
  19. 2026-07-04 06:29 UTCEPSS rescore
  20. 2026-07-01 15:04 UTCEPSS rescore
  21. 2026-06-30 23:20 UTCEPSS rescore
  22. 2026-06-30 23:20 UTCEPSS rescore
  23. 2026-06-29 14:04 UTCEPSS rescore
  24. 2026-06-28 14:05 UTCEPSS rescore
  25. 2026-06-28 04:54 UTCEPSS rescore
Show 62 more
  1. 2026-06-28 04:54 UTCEPSS rescore
  2. 2026-06-27 03:06 UTCEPSS rescore
  3. 2026-06-25 13:48 UTCEPSS rescore
  4. 2026-06-25 13:48 UTCEPSS rescore
  5. 2026-06-24 14:03 UTCEPSS rescore
  6. 2026-06-24 14:03 UTCEPSS rescore
  7. 2026-06-23 21:31 UTCEPSS rescore
  8. 2026-06-23 21:31 UTCEPSS rescore
  9. 2026-06-22 14:24 UTCEPSS rescore
  10. 2026-06-22 14:24 UTCEPSS rescore
  11. 2026-06-21 14:55 UTCEPSS rescore
  12. 2026-06-21 01:58 UTCEPSS rescore
  13. 2026-06-21 01:58 UTCEPSS rescore
  14. 2026-06-19 19:24 UTCEPSS rescore
  15. 2026-06-19 19:24 UTCEPSS rescore
  16. 2026-06-18 17:51 UTCEPSS rescore
  17. 2026-06-18 17:51 UTCEPSS rescore
  18. 2026-06-17 17:51 UTCEPSS rescore
  19. 2026-06-16 17:51 UTCEPSS rescore
  20. 2026-06-16 17:51 UTCEPSS rescore
  21. 2026-06-15 17:46 UTCEPSS rescore
  22. 2026-06-14 23:15 UTCEPSS rescore
  23. 2026-06-13 22:58 UTCEPSS rescore
  24. 2026-06-13 22:58 UTCEPSS rescore
  25. 2026-06-12 23:10 UTCEPSS rescore
  26. 2026-06-12 23:10 UTCEPSS rescore
  27. 2026-06-11 13:58 UTCEPSS rescore
  28. 2026-06-10 22:16 UTCEPSS rescore
  29. 2026-06-10 13:20 UTCEPSS rescore
  30. 2026-06-08 14:15 UTCEPSS rescore
  31. 2026-06-08 14:15 UTCEPSS rescore
  32. 2026-06-07 15:23 UTCEPSS rescore
  33. 2026-06-07 15:23 UTCEPSS rescore
  34. 2026-06-06 13:46 UTCEPSS rescore
  35. 2026-06-06 13:46 UTCEPSS rescore
  36. 2026-06-06 13:46 UTCEPSS rescore
  37. 2026-06-05 22:45 UTCEPSS rescore
  38. 2026-06-05 06:09 UTCEPSS rescore
  39. 2026-06-05 06:09 UTCEPSS rescore
  40. 2026-06-04 13:10 UTCEPSS rescore
  41. 2026-06-04 13:10 UTCEPSS rescore
  42. 2026-06-02 20:11 UTCEPSS rescore
  43. 2026-06-02 20:11 UTCEPSS rescore
  44. 2026-06-01 13:50 UTCEPSS rescore
  45. 2026-06-01 13:50 UTCEPSS rescore
  46. 2026-05-31 22:29 UTCEPSS rescore
  47. 2026-05-31 22:29 UTCEPSS rescore
  48. 2026-05-31 00:15 UTCEPSS rescore
  49. 2026-05-31 00:15 UTCEPSS rescore
  50. 2026-05-29 13:42 UTCEPSS rescore
  51. 2026-05-29 13:42 UTCEPSS rescore
  52. 2026-05-28 13:43 UTCEPSS rescore
  53. 2026-05-28 13:43 UTCEPSS rescore
  54. 2026-05-27 13:39 UTCEPSS rescore
  55. 2026-05-27 13:39 UTCEPSS rescore
  56. 2026-05-27 13:39 UTCEPSS rescore
  57. 2026-05-26 14:48 UTCEG score recompute
  58. 2026-05-26 14:48 UTCGHSA enrichment
  59. 2026-05-26 13:42 UTCEPSS rescore
  60. 2026-05-26 07:17 UTCEPSS rescore
  61. 2026-05-26 07:17 UTCEPSS rescore
  62. 2026-05-26 07:17 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-34203?
CVE-2021-34203 is a high vulnerability published on June 16, 2021. D-Link DIR-2640-US 1.01B04 is vulnerable to Incorrect Access Control. Router ac2600 (dir-2640-us), when setting PPPoE, will start quagga process in the way of whole network monitoring, and this function uses the original default password and port. An attacker can easily use telnet to log in, modify…
When was CVE-2021-34203 disclosed?
CVE-2021-34203 was first published in the National Vulnerability Database on June 16, 2021, with the most recent update on July 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-34203 actively exploited?
CVE-2021-34203 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 65.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-34203?
CVE-2021-34203 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2021-34203?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-34203, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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