CVE-2021-39537

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 3%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

An issue was discovered in ncurses through v6.2-1. _nc_captoinfo in captoinfo.c has a heap-based buffer overflow.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity88% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
3%
EPSS %ILE
87%
KEV
Not listed

Published

September 20, 2021

Last Modified

July 27, 2026

Advisory Details (10)

Auto-updated Jul 27, 2026
⚠️ Active exploitation confirmed. Patch available.
generic

About the security content of macOS Big Sur 11.7 - Apple Support

https://support.apple.com/kb/HT213443
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20230427-0012/
generic

Re: CVE-2021-39537

https://lists.gnu.org/archive/html/bug-ncurses/2021-10/msg00023.html
generic

A heap-buffer-overflow in captoinfo.c:321:12

https://lists.gnu.org/archive/html/bug-ncurses/2020-08/msg00006.html
generic Patch Available

[SECURITY] [DLA 3682-1] ncurses security update

https://lists.debian.org/debian-lts-announce/2023/12/msg00004.html
generic🔴 Active Exploitation

Full Disclosure: APPLE-SA-2022-10-27-9 Additional information for APPLE-SA-2022-09-12-3 macOS Big Sur 11.7

http://seclists.org/fulldisclosure/2022/Oct/45
generic🔴 Active Exploitation

Full Disclosure: APPLE-SA-2022-10-27-7 Additional information for APPLE-SA-2022-09-12-4 macOS Monterey 12.6

http://seclists.org/fulldisclosure/2022/Oct/43
generic

Full Disclosure: APPLE-SA-2022-10-27-5 Additional information for APPLE-SA-2022-10-24-2 macOS Ventura 13

http://seclists.org/fulldisclosure/2022/Oct/41
generic

Full Disclosure: APPLE-SA-2022-10-24-2 macOS Ventura 13

http://seclists.org/fulldisclosure/2022/Oct/28
generic

pkgsrc/devel/ncurses/patches/patch-ncurses_tinfo_captoinfo.c - view - 1.1

http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/devel/ncurses/patches/patch-ncurses_tinfo_captoinfo.c?rev=1.1&content-type=text/x-cvsweb-markup

Vendor Advisories for CVE-2021-39537(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
ubuntuncurses-term (6.0+20160213-1ubuntu1+esm2) @ xenial2026-05-23ubuntu
ubuntuncurses-term (5.9+20140118-1ubuntu1+esm3) @ trusty2026-05-23ubuntu

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

(18 across 18 ecosystems)
Alpine:v3.12(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200523-r1—
Alpine:v3.13(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.14(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.15(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.16(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.17(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.18(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.19(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2_p20200530-r0—
Debian:10(1)
PackageVulnerable rangeFixed inDependents
ncurses6.1+20181013-2, 6.1+20181013-2+deb10u1, 6.1+20181013-2+deb10u2, 6.1+20181013-2+deb10u3, 6.1+20181013-2+deb10u46.1+20181013-2+deb10u5—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2+20200912-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2+20200912-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2+20200912-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
ncurses—6.2+20200912-1—

Weakness Classification(1)

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

All Vendor Advisories

(3)

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 7× in last 7d / 31× 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 155 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2021-39537?
CVE-2021-39537 is a high vulnerability published on September 20, 2021. An issue was discovered in ncurses through v6.2-1. nccaptoinfo in captoinfo.c has a heap-based buffer overflow.
When was CVE-2021-39537 disclosed?
CVE-2021-39537 was first published in the National Vulnerability Database on September 20, 2021, with the most recent update on July 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-39537 actively exploited?
CVE-2021-39537 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 3% probability of exploitation in the next 30 days, which ranks it in the top 12.6% of all scored CVEs.
What is the CVSS score of CVE-2021-39537?
CVE-2021-39537 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-39537?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-39537, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-39537

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