CVE-2021-0255

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 89% of all CVEs by exploit prediction. 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
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

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

A local privilege escalation vulnerability in ethtraceroute of Juniper Networks Junos OS may allow a locally authenticated user with shell access to escalate privileges and write to the local filesystem as root. ethtraceroute is shipped with setuid permissions enabled and is owned by the root user, allowing local users to run ethtraceroute with root privileges. This issue affects Juniper Networks Junos OS: 15.1X49 versions prior to 15.1X49-D240; 17.3 versions prior to 17.3R3-S11, 17.4 versions prior to 17.4R3-S4; 18.1 versions prior to 18.1R3-S12; 18.2 versions prior to 18.2R3-S7; 18.3 versions prior to 18.3R3-S4; 18.4 versions prior to 18.4R2-S7; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3-S4; 19.3 versions prior to 19.3R3-S2; 19.4 versions prior to 19.4R3-S1; 20.1 versions prior to 20.1R2, 20.1R3; 20.2 versions prior to 20.2R2-S1, 20.2R3; 20.3 versions prior to 20.3R1-S1.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
—
EPSS
10.6%
KEV
Not listed

Published

April 22, 2021

Last Modified

November 21, 2024

References (2)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 43× 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. 2026-07-22 22:42 UTCEG score recompute
  2. 2026-07-22 14:05 UTCEPSS rescore
  3. 2026-07-21 15:22 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-20 17:04 UTCEPSS rescore
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  1. 2026-07-04 06:29 UTCEPSS rescore
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  3. 2026-07-02 16:57 UTCEPSS rescore
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  5. 2026-06-30 23:20 UTCEPSS rescore
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  7. 2026-06-29 14:04 UTCEPSS rescore
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  11. 2026-06-27 03:06 UTCEPSS rescore
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  17. 2026-06-23 21:31 UTCEPSS rescore
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  19. 2026-06-22 14:23 UTCEPSS rescore
  20. 2026-06-21 14:54 UTCEPSS rescore
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  22. 2026-06-21 01:57 UTCEPSS rescore
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  24. 2026-06-19 19:24 UTCEPSS rescore
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  26. 2026-06-18 17:51 UTCEPSS rescore
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  28. 2026-06-16 17:50 UTCEPSS rescore
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  30. 2026-06-14 23:15 UTCEPSS rescore
  31. 2026-06-13 22:58 UTCEPSS rescore
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  35. 2026-06-11 13:58 UTCEPSS rescore
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  37. 2026-06-10 22:16 UTCEPSS rescore
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  39. 2026-06-08 14:15 UTCEPSS rescore
  40. 2026-06-06 13:46 UTCEPSS rescore
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  43. 2026-06-05 22:45 UTCEPSS rescore
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  45. 2026-06-05 06:08 UTCEPSS rescore
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  47. 2026-06-04 13:10 UTCEPSS rescore
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  49. 2026-06-02 20:11 UTCEPSS rescore
  50. 2026-06-02 20:11 UTCEPSS rescore
  51. 2026-06-01 13:50 UTCEPSS rescore
  52. 2026-05-31 22:29 UTCEPSS rescore
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  54. 2026-05-31 00:15 UTCEPSS rescore
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  56. 2026-05-29 13:42 UTCEPSS rescore
  57. 2026-05-28 13:43 UTCEPSS rescore
  58. 2026-05-28 13:43 UTCEPSS rescore
  59. 2026-05-27 13:39 UTCEPSS rescore
  60. 2026-05-27 13:39 UTCEPSS rescore
  61. 2026-05-26 17:57 UTCEG score recompute
  62. 2026-05-26 17:57 UTCGHSA enrichment
  63. 2026-05-26 13:42 UTCEPSS rescore
  64. 2026-05-26 13:42 UTCEPSS rescore
  65. 2026-05-26 07:17 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-0255?
CVE-2021-0255 is a medium vulnerability published on April 22, 2021. A local privilege escalation vulnerability in ethtraceroute of Juniper Networks Junos OS may allow a locally authenticated user with shell access to escalate privileges and write to the local filesystem as root. ethtraceroute is shipped with setuid permissions enabled and is owned by the root user,…
When was CVE-2021-0255 disclosed?
CVE-2021-0255 was first published in the National Vulnerability Database on April 22, 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-2021-0255 actively exploited?
CVE-2021-0255 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 10.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-0255?
CVE-2021-0255 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-0255?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-0255, 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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