CVE-2026-16411

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-21. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
Trending — 3 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 9.8Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

Memory safety bugs present in Firefox 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

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 (value × EchelonGraph’s weight)
Severity98% × 45%
The EG Score, 9.8 of 10.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
40th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 21, 2026

Last Modified

July 24, 2026

Advisory Details (5)

Auto-updated Oct 9, 2026
Fix named in the CVE record.
Web page

Security Vulnerabilities fixed in Thunderbird 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-71/
Web page

Security Vulnerabilities fixed in Firefox 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-68/
Web page

Client Challenge

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048936%2C2049804
Web page

Client Challenge

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2006467%2C2027346%2C2027349%2C2027353%2C2027362%2C2027371%2C2027373%2C2028954%2C2029694%2C2036906%2C2038964%2C2039460%2C2040522%2C2040834%2C2043275%2C2045394%2C2045606%2C2052060
Web page

Client Challenge

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1420800%2C1598946%2C1767921%2C2013993%2C2025417%2C2027325%2C2027364%2C2029433%2C2029807%2C2029901%2C2029922%2C2030102%2C2030563%2C2032110%2C2037801%2C2042756%2C2044625%2C2045609%2C2047920%2C2048491%2C2048492%2C2048800%2C2050534%2C2050662%2C2050871

Vendor Advisories for CVE-2026-16411(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 17× in last 7d / 61× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 590 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 490 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-10-14 11:07 UTCEG score recompute
  3. 2026-10-14 11:07 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-13 09:51 UTCEG score recompute
  6. 2026-10-13 09:51 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  8. 2026-10-12 16:30 UTCEG score recompute
  9. 2026-10-12 09:35 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  10. 2026-10-11 20:09 UTCEG score recompute
  11. 2026-10-11 17:21 UTCEG score recompute
  12. 2026-10-11 14:54 UTCEG score recompute
  13. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  14. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  15. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  16. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  17. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  18. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  19. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  20. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  21. 2026-10-04 14:50 UTCEG score recompute
  22. 2026-10-04 14:50 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  24. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  25. 2026-10-01 15:04 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 75 more
  1. 2026-10-01 11:18 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  2. 2026-10-01 07:31 UTCEG score recompute
  3. 2026-10-01 07:31 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  6. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  7. 2026-09-28 13:35 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-09-28 09:53 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-09-28 06:11 UTCEG score recompute
  10. 2026-09-28 06:11 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-09-27 13:47 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  12. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-09-24 12:00 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-09-24 08:17 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-09-24 03:24 UTCEG score recompute
  16. 2026-09-24 03:24 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-09-23 09:12 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-09-23 05:24 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  19. 2026-09-23 01:27 UTCEG score recompute
  20. 2026-09-23 01:27 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-09-20 05:59 UTCEG score recompute
  22. 2026-09-20 05:59 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-09-19 00:23 UTCEG score recompute
  24. 2026-09-19 00:23 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  26. 2026-09-18 11:17 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  27. 2026-09-18 07:34 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-09-18 03:51 UTCEG score recompute
  29. 2026-09-18 03:51 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  30. 2026-09-17 09:53 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  31. 2026-09-17 05:07 UTCEG score recompute
  32. 2026-09-17 05:07 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  33. 2026-09-16 14:07 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  34. 2026-09-16 12:40 UTCEG score recompute
  35. 2026-09-16 12:40 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  36. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  37. 2026-09-14 10:19 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  38. 2026-09-14 06:06 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-09-14 02:23 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  40. 2026-09-13 22:40 UTCEG score recompute
  41. 2026-09-13 22:40 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  43. 2026-09-13 15:57 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  44. 2026-09-13 11:26 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-09-13 07:02 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  46. 2026-09-13 03:00 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  47. 2026-09-12 19:11 UTCEG score recompute
  48. 2026-09-12 19:11 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  50. 2026-09-12 13:30 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  51. 2026-09-12 09:48 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-09-12 05:48 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-09-12 01:50 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  54. 2026-09-11 22:07 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-09-11 18:17 UTCEG score recompute
  56. 2026-09-11 18:17 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  58. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  59. 2026-09-11 09:07 UTCEG score recompute
  60. 2026-09-11 09:07 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  62. 2026-09-09 11:34 UTCEG score recompute
  63. 2026-09-09 11:34 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  65. 2026-09-08 02:23 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  66. 2026-09-07 22:40 UTCEG score recompute
  67. 2026-09-07 22:40 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  68. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  69. 2026-09-06 18:48 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  70. 2026-09-06 14:44 UTCEG score recompute
  71. 2026-09-06 14:44 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  73. 2026-09-06 11:01 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-09-06 04:02 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8
  75. 2026-09-05 23:33 UTCGHSA enrichmentGHSA-jxhp-8w98-jhcf · GitHub severity CRITICAL · GitHub CVSS 9.8

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-16411?
CVE-2026-16411 is a critical-severity vulnerability; its CVE record was published on July 21, 2026. Memory safety bugs present in Firefox 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 153 and Thunderbird 153.
When was the CVE record for CVE-2026-16411 published?
The CVE record for CVE-2026-16411 was published on July 21, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 24, 2026; the record at its source may have been updated since.
Is CVE-2026-16411 actively exploited?
CVE-2026-16411 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-16411?
CVE-2026-16411 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-16411?
The CVE record for CVE-2026-16411 names the fix: "This vulnerability was fixed in Firefox 153 and Thunderbird 153." The vendor advisories EchelonGraph has for CVE-2026-16411 are linked in the Vendor Advisories panel on this page.

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