CVE-2021-33910

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 9%CVSS: 5.5Exploit: NoneExposed: 0

A fix is available — apply it.

basic/unit-name.c in systemd prior to 246.15, 247.8, 248.5, and 249.1 has a Memory Allocation with an Excessive Size Value (involving strdupa and alloca for a pathname controlled by a local attacker) that results in an operating system crash.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: Track

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
Severity55% × 45%
Exploitation9% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
94.6%
KEV
Not listed

Published

July 20, 2021

Last Modified

June 9, 2025

References (34)

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuudev (247.3-3ubuntu3.4) @ hirsute2026-05-26ubuntu
ubuntuudev-udeb (229-4ubuntu21.31+esm1) @ xenial2026-05-26ubuntu
redhatredhat-virtualization-host-0:4.4.7-20210715.1.el8_42021-07-22redhat
redhatsystemd-0:239-45.el8_4.22021-07-21redhat
redhatsystemd-0:239-18.el8_1.82021-07-20redhat
redhatsystemd-0:239-31.el8_2.42021-07-20redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

All Vendor Advisories

(7)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 17× in last 7d / 48× 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 103 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-33910?
CVE-2021-33910 is a medium vulnerability published on July 20, 2021. basic/unit-name.c in systemd prior to 246.15, 247.8, 248.5, and 249.1 has a Memory Allocation with an Excessive Size Value (involving strdupa and alloca for a pathname controlled by a local attacker) that results in an operating system crash.
When was CVE-2021-33910 disclosed?
CVE-2021-33910 was first published in the National Vulnerability Database on July 20, 2021, with the most recent update on June 9, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-33910 actively exploited?
CVE-2021-33910 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 94.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-33910?
CVE-2021-33910 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2021-33910?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-33910, 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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