CVE-2021-0205

MEDIUMNVD 5.85.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.8 under NVD CVSS v3. EPSS exploit probability: 1.2% (67th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1.2%CVSS: 5.8Exploit: None knownExposed services: Not assessed

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

When the "Intrusion Detection Service" (IDS) feature is configured on Juniper Networks MX series with a dynamic firewall filter using IPv6 source or destination prefix, it may incorrectly match the prefix as /32, causing the filter to block unexpected traffic. This issue affects only IPv6 prefixes when used as source and destination. This issue affects MX Series devices using MS-MPC, MS-MIC or MS-SPC3 service cards with IDS service configured. This issue affects: Juniper Networks Junos OS 17.3 versions prior to 17.3R3-S10 on MX Series; 17.4 versions prior to 17.4R3-S3 on MX Series; 18.1 versions prior to 18.1R3-S11 on MX Series; 18.2 versions prior to 18.2R3-S6 on MX Series; 18.3 versions prior to 18.3R3-S4 on MX Series; 18.4 versions prior to 18.4R3-S6 on MX Series; 19.1 versions prior to 19.1R2-S2, 19.1R3-S3 on MX Series; 19.2 versions prior to 19.2R3-S1 on MX Series; 19.3 versions prior to 19.3R2-S5, 19.3R3-S1 on MX Series; 19.4 versions prior to 19.4R3 on MX Series; 20.1 versions prior to 20.1R2 on MX Series; 20.2 versions prior to 20.2R2 on MX Series;

CVSS v3
5.8
EG Score
5.8MEDIUMmedium confidence
EG Risk
31
EG Risk 31/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity58% × 45%
Exploitation1% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
1.2%
EPSS %ILE
67th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

January 15, 2021

Last Modified

November 21, 2024

References (2)

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 24× 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.

Showing the most recent 100 of 157 total refreshes for this CVE.

  1. 2026-10-03 14:22 UTCEPSS rescore
  2. 2026-10-03 14:22 UTCEPSS rescore
  3. 2026-10-02 16:22 UTCEPSS rescore
  4. 2026-10-01 19:46 UTCEPSS rescore
  5. 2026-09-30 15:26 UTCEG score recompute
  6. 2026-09-30 14:59 UTCEPSS rescore
  7. 2026-09-27 13:41 UTCEPSS rescore
  8. 2026-09-26 15:54 UTCEPSS rescore
  9. 2026-09-26 15:54 UTCEPSS rescore
  10. 2026-09-26 00:21 UTCEPSS rescore
  11. 2026-09-24 14:00 UTCEPSS rescore
  12. 2026-09-22 14:44 UTCEPSS rescore
  13. 2026-09-21 20:28 UTCEPSS rescore
  14. 2026-09-19 15:37 UTCEPSS rescore
  15. 2026-09-18 19:23 UTCEPSS rescore
  16. 2026-09-17 19:22 UTCEPSS rescore
  17. 2026-09-16 14:04 UTCEPSS rescore
  18. 2026-09-15 03:06 UTCEPSS rescore
  19. 2026-09-13 16:43 UTCEPSS rescore
  20. 2026-09-12 14:57 UTCEPSS rescore
  21. 2026-09-08 21:56 UTCEPSS rescore
  22. 2026-09-07 15:58 UTCEPSS rescore
  23. 2026-09-06 13:44 UTCEPSS rescore
  24. 2026-09-05 15:25 UTCEPSS rescore
  25. 2026-09-04 13:57 UTCEPSS rescore
Show 75 more
  1. 2026-09-04 13:57 UTCEPSS rescore
  2. 2026-09-04 05:03 UTCEPSS rescore
  3. 2026-09-02 14:08 UTCEPSS rescore
  4. 2026-09-01 03:32 UTCEPSS rescore
  5. 2026-08-30 19:14 UTCEPSS rescore
  6. 2026-08-30 01:19 UTCEPSS rescore
  7. 2026-08-28 21:37 UTCEPSS rescore
  8. 2026-08-27 14:21 UTCEPSS rescore
  9. 2026-08-26 14:42 UTCEPSS rescore
  10. 2026-08-21 23:45 UTCEPSS rescore
  11. 2026-08-19 17:00 UTCEPSS rescore
  12. 2026-08-18 13:44 UTCEPSS rescore
  13. 2026-08-17 13:43 UTCEPSS rescore
  14. 2026-08-17 13:43 UTCEPSS rescore
  15. 2026-08-16 14:52 UTCEPSS rescore
  16. 2026-08-16 02:11 UTCEPSS rescore
  17. 2026-08-15 01:27 UTCEPSS rescore
  18. 2026-08-13 21:57 UTCEPSS rescore
  19. 2026-08-12 13:47 UTCEPSS rescore
  20. 2026-08-09 13:43 UTCEPSS rescore
  21. 2026-08-08 16:33 UTCEPSS rescore
  22. 2026-08-07 16:23 UTCEPSS rescore
  23. 2026-08-06 13:43 UTCEPSS rescore
  24. 2026-08-05 19:14 UTCEPSS rescore
  25. 2026-08-04 15:06 UTCEPSS rescore
  26. 2026-08-04 10:34 UTCEPSS rescore
  27. 2026-08-02 02:24 UTCEPSS rescore
  28. 2026-08-01 04:12 UTCEPSS rescore
  29. 2026-07-30 16:25 UTCEPSS rescore
  30. 2026-07-30 01:27 UTCEPSS rescore
  31. 2026-07-28 15:33 UTCEPSS rescore
  32. 2026-07-26 14:52 UTCEPSS rescore
  33. 2026-07-25 14:15 UTCEPSS rescore
  34. 2026-07-23 14:15 UTCEPSS rescore
  35. 2026-07-23 01:56 UTCEG score recompute
  36. 2026-07-22 22:42 UTCEG score recompute
  37. 2026-07-22 14:05 UTCEPSS rescore
  38. 2026-07-21 15:22 UTCEPSS rescore
  39. 2026-07-21 15:22 UTCEPSS rescore
  40. 2026-07-20 17:04 UTCEPSS rescore
  41. 2026-07-20 17:04 UTCEPSS rescore
  42. 2026-07-19 14:28 UTCEPSS rescore
  43. 2026-07-19 14:28 UTCEPSS rescore
  44. 2026-07-19 02:26 UTCEPSS rescore
  45. 2026-07-19 02:26 UTCEPSS rescore
  46. 2026-07-18 10:02 UTCEPSS rescore
  47. 2026-07-16 17:00 UTCEPSS rescore
  48. 2026-07-15 16:55 UTCEPSS rescore
  49. 2026-07-15 16:55 UTCEPSS rescore
  50. 2026-07-15 01:57 UTCEPSS rescore
  51. 2026-07-13 22:27 UTCEPSS rescore
  52. 2026-07-13 22:27 UTCEPSS rescore
  53. 2026-07-12 05:44 UTCEPSS rescore
  54. 2026-07-12 05:44 UTCEPSS rescore
  55. 2026-07-11 08:25 UTCEPSS rescore
  56. 2026-07-11 08:25 UTCEPSS rescore
  57. 2026-07-09 19:07 UTCEPSS rescore
  58. 2026-07-08 15:12 UTCEPSS rescore
  59. 2026-07-07 13:43 UTCEPSS rescore
  60. 2026-07-06 16:25 UTCEPSS rescore
  61. 2026-07-06 02:21 UTCEPSS rescore
  62. 2026-07-06 02:21 UTCEPSS rescore
  63. 2026-07-05 02:28 UTCEPSS rescore
  64. 2026-07-05 02:28 UTCEPSS rescore
  65. 2026-07-04 06:29 UTCEPSS rescore
  66. 2026-07-04 06:29 UTCEPSS rescore
  67. 2026-07-02 16:57 UTCEPSS rescore
  68. 2026-07-01 15:03 UTCEPSS rescore
  69. 2026-06-30 23:20 UTCEPSS rescore
  70. 2026-06-30 23:20 UTCEPSS rescore
  71. 2026-06-29 14:04 UTCEPSS rescore
  72. 2026-06-28 04:54 UTCEPSS rescore
  73. 2026-06-28 04:54 UTCEPSS rescore
  74. 2026-06-27 03:06 UTCEPSS rescore
  75. 2026-06-27 03:06 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-0205?
CVE-2021-0205 is a medium vulnerability published on January 15, 2021. When the "Intrusion Detection Service" (IDS) feature is configured on Juniper Networks MX series with a dynamic firewall filter using IPv6 source or destination prefix, it may incorrectly match the prefix as /32, causing the filter to block unexpected traffic. This issue affects only IPv6 prefixes…
When was CVE-2021-0205 disclosed?
CVE-2021-0205 was first published on January 15, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-0205 actively exploited?
CVE-2021-0205 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.2% probability of exploitation in the next 30 days (67th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-0205?
CVE-2021-0205 has a CVSS v3 base score of 5.8 (NVD).
How do I remediate CVE-2021-0205?
No fix for CVE-2021-0205 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-0205

Explore →

Is Your Infrastructure Affected by CVE-2021-0205?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs