CVE-2026-74953

HIGHPre-NVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-18. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Privilege escalation in the Networking: Cookies component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100CISA SSVC

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%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
36th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 18, 2026

Last Modified

August 21, 2026

Advisory Details (4)

Auto-updated Aug 18, 2026
Patch available.
generic

Security Vulnerabilities fixed in Firefox ESR 153.1 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-77/
generic

Security Vulnerabilities fixed in Firefox ESR 140.14 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-76/
generic

Security Vulnerabilities fixed in Firefox 154 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2026-74/
generic

Access Denied

https://bugzilla.mozilla.org/show_bug.cgi?id=2022382

Vendor Advisories for CVE-2026-74953(13)

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

Patch Availability(17)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatthunderbird-0:140.14.0-1.el8_42026-09-09redhat
redhatthunderbird-0:140.14.0-1.el8_82026-09-09redhat
redhatfirefox-0:140.14.0-1.el9_22026-09-09redhat
redhatthunderbird-0:140.14.0-1.el8_62026-09-09redhat
redhatfirefox-0:140.14.0-1.el8_82026-09-08redhat
redhatfirefox-0:140.14.0-1.el10_02026-09-08redhat
redhatfirefox-0:140.14.0-1.el7_92026-09-08redhat
redhatfirefox-0:140.14.0-1.el8_62026-09-08redhat
redhatthunderbird-0:140.14.0-1.el10_22026-09-08redhat
redhatthunderbird-0:140.14.0-1.el10_02026-09-08redhat
redhatthunderbird-0:140.14.0-1.el8_102026-09-08redhat
redhatfirefox-0:140.14.0-1.el8_42026-09-08redhat
redhatfirefox-0:140.14.0-1.el9_42026-09-08redhat
redhatfirefox-0:140.14.0-1.el9_62026-09-08redhat
redhatfirefox-0:140.14.0-1.el9_82026-08-24redhat
redhatfirefox-0:140.14.0-1.el10_22026-08-24redhat
redhatfirefox-0:140.14.0-1.el8_102026-08-24redhat

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

(6 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr102.11.0esr-1 ... 140.9.1esr-1~deb13u1 (195 versions)
  • every version up to 140.14.0esr-1~deb12u1: fixed in 140.14.0esr-1~deb12u1
—
thunderbird1:102.11.0-1 ... 1:140.9.1esr-1~deb13u1 (224 versions)
  • every version up to 1:140.14.0esr-1~deb12u1: fixed in 1:140.14.0esr-1~deb12u1
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (71 versions)
  • every version up to 140.14.0esr-1~deb13u1: fixed in 140.14.0esr-1~deb13u1
—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (80 versions)
  • every version up to 1:140.14.0esr-1~deb13u1: fixed in 1:140.14.0esr-1~deb13u1
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr128.13.0esr-1 ... 140.9.1esr-1~deb13u1 (72 versions)
  • every version up to 140.14.0esr-2: fixed in 140.14.0esr-2
—
thunderbird1:128.13.0esr-1 ... 1:140.9.1esr-1~deb13u1 (81 versions)
  • every version up to 1:140.14.0esr-1: fixed in 1:140.14.0esr-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(5)

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 29× in last 7d / 143× 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 239 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-74953?
CVE-2026-74953 is a high vulnerability published on August 18, 2026. Privilege escalation in the Networking: Cookies component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
When was CVE-2026-74953 disclosed?
CVE-2026-74953 was first published on August 18, 2026, with the most recent update on August 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74953 actively exploited?
CVE-2026-74953 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-74953?
CVE-2026-74953 has a CVSS v3.1 base score of 8.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-74953?
A fix for CVE-2026-74953 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-74953 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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