CVE-2026-78209

HIGHPre-NVD 8.28.2—
EchelonGraph scoreHIGH confidence

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-08-24. a secondary CVSS source baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: None knownExposed: 0

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

exceljs through 4.4.0 fails to neutralize leading equals, plus, minus, or at signs in cell values written to CSV output. Attackers who can influence exported cell values can inject formulas that execute when the CSV file is opened in a spreadsheet application, potentially exfiltrating data or performing other malicious actions.

CVSS v3
8.2
EG Score
8.2(high)
EG Risk
37(Track)
EG Risk 37/100SSVC: 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
Severity82% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

August 24, 2026

Last Modified

August 31, 2026

Advisory Details (4)

Auto-updated Aug 24, 2026
Patch available. Sources: github.
generic

exceljs through 4.4.0 CSV Formula Injection via Unescaped Cell Values | Advisories | VulnCheck

https://www.vulncheck.com/advisories/exceljs-through-csv-formula-injection-via-unescaped-cell-values
generic

exceljs/lib/csv/csv.js at v4.4.0 · exceljs/exceljs · GitHub

https://github.com/exceljs/exceljs/blob/v4.4.0/lib/csv/csv.js#L109-L182
github Patch Available

CSV Formula Injection in exceljs via `CSV.write()` · Advisory · mateocallec/exceljs-hardened · GitHub

https://github.com/mateocallec/exceljs-hardened/security/advisories/GHSA-9wxc-4rhw-hfrw
generic

GitHub - exceljs/exceljs: Excel Workbook Manager · GitHub

https://github.com/exceljs/exceljs

Vendor Advisories for CVE-2026-78209(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 26× in last 7d / 115× 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 115 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-78209?
CVE-2026-78209 is a high vulnerability published on August 24, 2026. exceljs through 4.4.0 fails to neutralize leading equals, plus, minus, or at signs in cell values written to CSV output. Attackers who can influence exported cell values can inject formulas that execute when the CSV file is opened in a spreadsheet application, potentially exfiltrating data or…
When was CVE-2026-78209 disclosed?
CVE-2026-78209 was first published in the National Vulnerability Database on August 24, 2026, with the most recent update on August 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-78209 actively exploited?
CVE-2026-78209 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 77.6% of all scored CVEs.
What is the CVSS score of CVE-2026-78209?
CVE-2026-78209 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-78209?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-78209, 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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