CVE-2021-39843

HIGHNVD 7.88.8▲
EchelonGraph scoreHIGH confidence

Score elevated to 8.8 because EPSS predicts 76% probability of exploitation within the next 30 days (top 0.5% of all CVEs). NVD baseline CVSS 7.8 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, nvd
Elevated
8.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 77%
CISA-KEV: Not listedEPSS PROB: 77%CVSS: 7.8Exploit: Elevated riskExposed: 0

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

Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an out-of-bounds write vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

CVSS v3
7.8
EG Score
8.8(high)
EG Risk
75(Track)
EG Risk 75/100SSVC: 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%
Exploitation76% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
77%
EPSS %ILE
100%
KEV
Not listed

Published

September 29, 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 4× in last 7d / 19× 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. 2026-09-07 15:58 UTCEPSS rescore
  2. 2026-09-06 13:45 UTCEPSS rescore
  3. 2026-09-05 15:25 UTCEPSS rescore
  4. 2026-09-02 14:09 UTCEPSS rescore
  5. 2026-08-30 19:14 UTCEPSS rescore
  6. 2026-08-30 19:14 UTCEPSS rescore
  7. 2026-08-30 01:19 UTCEPSS rescore
  8. 2026-08-28 21:37 UTCEPSS rescore
  9. 2026-08-26 14:43 UTCEPSS rescore
  10. 2026-08-25 13:46 UTCEPSS rescore
  11. 2026-08-24 14:13 UTCEPSS rescore
  12. 2026-08-21 23:46 UTCEPSS rescore
  13. 2026-08-19 17:01 UTCEPSS rescore
  14. 2026-08-18 13:45 UTCEPSS rescore
  15. 2026-08-17 13:44 UTCEPSS rescore
  16. 2026-08-16 14:53 UTCEPSS rescore
  17. 2026-08-16 02:11 UTCEPSS rescore
  18. 2026-08-13 21:57 UTCEPSS rescore
  19. 2026-08-12 13:48 UTCEPSS rescore
  20. 2026-08-08 16:33 UTCEPSS rescore
  21. 2026-08-07 16:24 UTCEPSS rescore
  22. 2026-08-06 13:44 UTCEPSS rescore
  23. 2026-07-30 16:25 UTCEPSS rescore
  24. 2026-07-26 14:52 UTCEPSS rescore
  25. 2026-07-26 14:52 UTCEPSS rescore
Show 69 more
  1. 2026-07-24 14:15 UTCEPSS rescore
  2. 2026-07-23 14:16 UTCEPSS rescore
  3. 2026-07-23 02:04 UTCEG score recompute▲ 1.00
  4. 2026-07-22 22:50 UTCEG score recompute
  5. 2026-07-22 14:06 UTCEPSS rescore
  6. 2026-07-20 17:05 UTCEPSS rescore
  7. 2026-07-15 16:55 UTCEPSS rescore
  8. 2026-07-15 16:55 UTCEPSS rescore
  9. 2026-07-13 06:11 UTCEPSS rescore
  10. 2026-07-13 06:11 UTCEPSS rescore
  11. 2026-07-11 08:25 UTCEPSS rescore
  12. 2026-07-11 08:25 UTCEPSS rescore
  13. 2026-07-09 19:07 UTCEPSS rescore
  14. 2026-07-06 16:25 UTCEPSS rescore
  15. 2026-07-06 16:25 UTCEPSS rescore
  16. 2026-07-02 16:57 UTCEPSS rescore
  17. 2026-06-30 23:20 UTCEPSS rescore
  18. 2026-06-30 23:20 UTCEPSS rescore
  19. 2026-06-28 14:05 UTCEPSS rescore
  20. 2026-06-28 04:54 UTCEPSS rescore
  21. 2026-06-28 04:54 UTCEPSS rescore
  22. 2026-06-27 03:06 UTCEPSS rescore
  23. 2026-06-27 03:06 UTCEPSS rescore
  24. 2026-06-25 13:48 UTCEPSS rescore
  25. 2026-06-25 13:48 UTCEPSS rescore
  26. 2026-06-23 21:31 UTCEPSS rescore
  27. 2026-06-23 21:31 UTCEPSS rescore
  28. 2026-06-22 14:24 UTCEPSS rescore
  29. 2026-06-21 14:55 UTCEPSS rescore
  30. 2026-06-21 01:58 UTCEPSS rescore
  31. 2026-06-21 01:58 UTCEPSS rescore
  32. 2026-06-17 17:51 UTCEPSS rescore
  33. 2026-06-17 17:51 UTCEPSS rescore
  34. 2026-06-17 17:51 UTCEPSS rescore
  35. 2026-06-16 17:51 UTCEPSS rescore
  36. 2026-06-16 17:51 UTCEPSS rescore
  37. 2026-06-15 17:46 UTCEPSS rescore
  38. 2026-06-13 22:58 UTCEPSS rescore
  39. 2026-06-13 22:58 UTCEPSS rescore
  40. 2026-06-12 23:10 UTCEPSS rescore
  41. 2026-06-11 13:58 UTCEPSS rescore
  42. 2026-06-11 13:58 UTCEPSS rescore
  43. 2026-06-10 22:16 UTCEPSS rescore
  44. 2026-06-10 22:16 UTCEPSS rescore
  45. 2026-06-10 13:20 UTCEPSS rescore
  46. 2026-06-08 14:15 UTCEPSS rescore
  47. 2026-06-08 14:15 UTCEPSS rescore
  48. 2026-06-07 15:23 UTCEPSS rescore
  49. 2026-06-07 15:23 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. 2026-05-31 22:29 UTCEPSS rescore
  60. 2026-05-31 22:29 UTCEPSS rescore
  61. 2026-05-29 13:42 UTCEPSS rescore
  62. 2026-05-28 13:43 UTCEPSS rescore
  63. 2026-05-28 13:43 UTCEPSS rescore
  64. 2026-05-27 13:39 UTCEPSS rescore
  65. 2026-05-27 13:39 UTCEPSS rescore
  66. 2026-05-26 13:42 UTCEPSS rescore
  67. 2026-05-26 13:42 UTCEPSS rescore
  68. 2026-05-26 09:46 UTCEG score recompute
  69. 2026-05-26 09:46 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2021-39843?
CVE-2021-39843 is a high vulnerability published on September 29, 2021. Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an out-of-bounds write vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user…
When was CVE-2021-39843 disclosed?
CVE-2021-39843 was first published in the National Vulnerability Database on September 29, 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-2021-39843 actively exploited?
CVE-2021-39843 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 77% probability of exploitation in the next 30 days, which ranks it in the top 0.5% of all scored CVEs.
What is the CVSS score of CVE-2021-39843?
CVE-2021-39843 has a CVSS v3 base score of 7.8 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 8.8.
How do I remediate CVE-2021-39843?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-39843, 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

Explore the affected products and dependency analysis for CVE-2021-39843

Explore →

Is Your Infrastructure Affected by CVE-2021-39843?

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

Start Free Scan →Browse All CVEs