CVE-2021-27645

LOWNVD 2.52.5—
EchelonGraph scoreMEDIUM confidence

Score 2.5 from GitHub Security Advisory published 2022-05-24. NVD baseline CVSS 2.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
2.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 2.5Exploit: None knownExposed: 0

A fix is available — apply it.

The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29 through 2.33, when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system. This is related to netgroupcache.c.

CVSS v3
2.5
EG Score
2.5(medium)
EG Risk
11(Track)
EG Risk 11/100SSVC: 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
Severity25% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
31%
KEV
Not listed

Published

February 24, 2021

Last Modified

June 9, 2025

References (10)

Vendor Advisories for CVE-2021-27645(1)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulocales (2.34-0ubuntu3.2) @ impish2026-05-26ubuntu
redhatglibc-0:2.28-164.el82021-11-09redhat

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.

Affected Packages

(5 across 5 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
glibc2.28-10, 2.28-10+deb10u12.28-10+deb10u2—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
glibc—2.31-10—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
glibc—2.31-10—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
glibc—2.31-10—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
glibc—2.31-10—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 32× 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 167 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2021-27645?
CVE-2021-27645 is a low vulnerability published on February 24, 2021. The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29 through 2.33, when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system. This is related to netgroupcache.c.
When was CVE-2021-27645 disclosed?
CVE-2021-27645 was first published in the National Vulnerability Database on February 24, 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-2021-27645 actively exploited?
CVE-2021-27645 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 68.7% of all scored CVEs.
What is the CVSS score of CVE-2021-27645?
CVE-2021-27645 has a CVSS v3 base score of 2.5 (NVD).
How do I remediate CVE-2021-27645?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-27645, 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.

Dependency Blast Radius

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