CVE-2017-7821

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

A vulnerability where WebExtensions can download and attempt to open a file of some non-executable file types. This can be triggered without specific user interaction for the file download and open actions. This could be used to trigger known vulnerabilities in the programs that handle those document types. This vulnerability affects Firefox < 56.

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
78.2%
KEV
Not listed

Published

June 11, 2018

Last Modified

November 21, 2024

Advisory Details (4)

Auto-updated Jun 5, 2026
No patch confirmed yet.
generic

Security vulnerabilities fixed in Firefox 56 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2017-21/
generic

1346515 - (CVE-2017-7821) browser.downloads addon feature may be used for RCE

https://bugzilla.mozilla.org/show_bug.cgi?id=1346515
generic
http://www.securitytracker.com/id/1039465
generic
http://www.securityfocus.com/bid/101057

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntufirefox-testsuite (56.0+build6-0ubuntu0.14.04.1) @ trusty2026-05-28ubuntu

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

(1)

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 8× in last 7d / 42× 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. 2026-07-15 16:55 UTCEPSS rescore
  2. 2026-07-15 16:54 UTCEPSS rescore
  3. 2026-07-15 01:56 UTCEPSS rescore
  4. 2026-07-15 01:56 UTCEPSS rescore
  5. 2026-07-13 22:26 UTCEPSS rescore
  6. 2026-07-13 22:26 UTCEPSS rescore
  7. 2026-07-12 05:43 UTCEPSS rescore
  8. 2026-07-09 19:06 UTCEPSS rescore
  9. 2026-07-08 15:11 UTCEPSS rescore
  10. 2026-07-07 13:42 UTCEPSS rescore
  11. 2026-07-06 16:24 UTCEPSS rescore
  12. 2026-07-06 16:24 UTCEPSS rescore
  13. 2026-07-06 02:20 UTCEPSS rescore
  14. 2026-07-06 02:20 UTCEPSS rescore
  15. 2026-07-05 02:27 UTCEPSS rescore
  16. 2026-07-04 06:28 UTCEPSS rescore
  17. 2026-07-04 06:28 UTCEPSS rescore
  18. 2026-07-02 16:54 UTCEPSS rescore
  19. 2026-07-01 15:03 UTCEPSS rescore
  20. 2026-06-30 23:19 UTCEPSS rescore
  21. 2026-06-30 23:19 UTCEPSS rescore
  22. 2026-06-29 14:03 UTCEPSS rescore
  23. 2026-06-28 14:04 UTCEPSS rescore
  24. 2026-06-28 04:53 UTCEPSS rescore
  25. 2026-06-28 04:53 UTCEPSS rescore
Show 58 more
  1. 2026-06-27 03:06 UTCEPSS rescore
  2. 2026-06-25 13:47 UTCEPSS rescore
  3. 2026-06-24 14:02 UTCEPSS rescore
  4. 2026-06-24 14:02 UTCEPSS rescore
  5. 2026-06-23 21:30 UTCEPSS rescore
  6. 2026-06-23 21:30 UTCEPSS rescore
  7. 2026-06-22 14:23 UTCEPSS rescore
  8. 2026-06-22 14:23 UTCEPSS rescore
  9. 2026-06-21 14:54 UTCEPSS rescore
  10. 2026-06-21 14:54 UTCEPSS rescore
  11. 2026-06-21 01:57 UTCEPSS rescore
  12. 2026-06-21 01:57 UTCEPSS rescore
  13. 2026-06-19 19:23 UTCEPSS rescore
  14. 2026-06-19 19:23 UTCEPSS rescore
  15. 2026-06-18 17:50 UTCEPSS rescore
  16. 2026-06-17 17:50 UTCEPSS rescore
  17. 2026-06-16 17:50 UTCEPSS rescore
  18. 2026-06-15 17:45 UTCEPSS rescore
  19. 2026-06-14 23:14 UTCEPSS rescore
  20. 2026-06-14 23:14 UTCEPSS rescore
  21. 2026-06-13 22:58 UTCEPSS rescore
  22. 2026-06-13 22:57 UTCEPSS rescore
  23. 2026-06-12 23:09 UTCEPSS rescore
  24. 2026-06-12 23:09 UTCEPSS rescore
  25. 2026-06-11 13:57 UTCEPSS rescore
  26. 2026-06-10 22:15 UTCEPSS rescore
  27. 2026-06-10 13:19 UTCEPSS rescore
  28. 2026-06-08 14:14 UTCEPSS rescore
  29. 2026-06-08 14:14 UTCEPSS rescore
  30. 2026-06-07 15:22 UTCEPSS rescore
  31. 2026-06-07 15:22 UTCEPSS rescore
  32. 2026-06-06 13:45 UTCEPSS rescore
  33. 2026-06-06 13:45 UTCEPSS rescore
  34. 2026-06-05 22:44 UTCEPSS rescore
  35. 2026-06-05 22:44 UTCEPSS rescore
  36. 2026-06-05 06:08 UTCEPSS rescore
  37. 2026-06-05 06:08 UTCEPSS rescore
  38. 2026-06-04 13:10 UTCEPSS rescore
  39. 2026-06-04 13:10 UTCEPSS rescore
  40. 2026-06-02 20:11 UTCEPSS rescore
  41. 2026-06-02 20:11 UTCEPSS rescore
  42. 2026-06-01 13:49 UTCEPSS rescore
  43. 2026-06-01 13:49 UTCEPSS rescore
  44. 2026-05-31 22:28 UTCEPSS rescore
  45. 2026-05-31 00:14 UTCEPSS rescore
  46. 2026-05-31 00:14 UTCEPSS rescore
  47. 2026-05-29 13:41 UTCEPSS rescore
  48. 2026-05-28 13:42 UTCEPSS rescore
  49. 2026-05-28 13:42 UTCEPSS rescore
  50. 2026-05-28 06:50 UTCEG score recompute
  51. 2026-05-28 06:50 UTCVendor advisory
  52. 2026-05-28 06:50 UTCGHSA enrichment
  53. 2026-05-27 13:38 UTCEPSS rescore
  54. 2026-05-27 13:38 UTCEPSS rescore
  55. 2026-05-26 13:42 UTCEPSS rescore
  56. 2026-05-26 07:17 UTCEPSS rescore
  57. 2026-05-26 07:17 UTCEPSS rescore
  58. 2026-05-25 18:16 UTCOSV refresh

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Frequently asked(5)

What is CVE-2017-7821?
CVE-2017-7821 is a critical vulnerability published on June 11, 2018. A vulnerability where WebExtensions can download and attempt to open a file of some non-executable file types. This can be triggered without specific user interaction for the file download and open actions. This could be used to trigger known vulnerabilities in the programs that handle those…
When was CVE-2017-7821 disclosed?
CVE-2017-7821 was first published in the National Vulnerability Database on June 11, 2018, 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-2017-7821 actively exploited?
CVE-2017-7821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 78.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2017-7821?
CVE-2017-7821 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2017-7821?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2017-7821, 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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