CVE-2026-16381

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-21. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

Same-origin policy bypass in the Networking: DNS component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: 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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

July 21, 2026

Last Modified

July 24, 2026

Advisory Details (5)

Auto-updated Sep 7, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Thunderbird 140.13 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-72/
generic

Security Vulnerabilities fixed in Thunderbird 153 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-71/
generic🔴 Active Exploitation

Security Vulnerabilities fixed in Firefox ESR 140.13 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-70/
generic

Security Vulnerabilities fixed in Firefox 153 — Mozilla

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

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2041001

Vendor Advisories for CVE-2026-16381(20)

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

Patch Availability(21)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatfirefox-0:140.13.0-1.el8_42026-08-12redhat
redhatfirefox-0:140.13.0-1.el9_42026-08-12redhat
redhatfirefox-0:140.13.0-1.el7_92026-08-12redhat
redhatfirefox-0:140.13.0-1.el8_82026-08-12redhat
redhatfirefox-0:140.13.0-1.el8_62026-08-12redhat
redhatfirefox-0:140.13.0-1.el9_22026-08-12redhat
redhatfirefox-0:140.13.0-1.el10_02026-08-12redhat
redhatfirefox-0:140.13.0-1.el9_62026-08-12redhat
redhatthunderbird-0:140.13.0-1.el8_42026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_62026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_42026-08-11redhat
redhatthunderbird-0:140.13.0-1.el10_02026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_82026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_22026-08-11redhat
redhatthunderbird-0:140.13.0-1.el8_62026-08-11redhat
redhatthunderbird-0:140.13.0-1.el9_82026-08-04redhat
redhatthunderbird-0:140.13.0-1.el8_102026-08-04redhat
redhatfirefox-0:140.13.0-1.el9_82026-08-03redhat
redhatthunderbird-0:140.13.0-1.el10_22026-08-03redhat
redhatfirefox-0:140.13.0-1.el10_22026-07-28redhat
redhatfirefox-0:140.13.0-1.el8_102026-07-28redhat

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

(8 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (283 versions)140.13.0esr-1~deb11u1—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (334 versions)1:140.13.0esr-1—
Debian:12(2)
PackageVulnerable rangeFixed inDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (190 versions)140.13.0esr-1~deb12u1—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (220 versions)1:140.13.0esr-2~deb12u1—
Debian:13(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (66 versions)140.13.0esr-1~deb13u1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (76 versions)1:140.13.0esr-2~deb13u1—
Debian:14(2)
PackageVulnerable rangeFixed inDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (67 versions)140.13.0esr-1—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (73 versions)1:140.13.0esr-1—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 37× in last 7d / 279× 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 537 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-16381?
CVE-2026-16381 is a critical vulnerability published on July 21, 2026. Same-origin policy bypass in the Networking: DNS component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
When was CVE-2026-16381 disclosed?
CVE-2026-16381 was first published in the National Vulnerability Database on July 21, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-16381 actively exploited?
CVE-2026-16381 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 93.1% of all scored CVEs.
What is the CVSS score of CVE-2026-16381?
CVE-2026-16381 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-16381?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-16381, 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-2026-16381

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