CVE-2026-55666

CRITICALPre-NVD 9.39.3
EchelonGraph scoreMEDIUM confidence

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

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (33rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
9.3EG
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: 0.4%CVSS: 9.3Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13, in apps/meteor/app/apple/server/loginHandler.ts, handleIdentityToken parses a JWT issued by Apple during the OAuth flow. The try block checks for an email parameter. If the JWT does not contain an email address, the application falls back to accepting an arbitrary email value supplied directly in the request. Attackers are able to forge Apple JWTs that do not contain an email address and leverage this vulnerability to carry out account takeover attacks. This vulnerability is fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13.

CVSS v3
9.3
EG Score
9.3CRITICALmedium confidence
EG Risk
57
EG Risk 57/100

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)
Severity93% × 45%
The EG Score, 9.3 of 10.
Exploitation0.4% × 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
0.4%
EPSS %ILE
33rd
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

June 24, 2026

Last Modified

June 29, 2026

Advisory Details (1)

Auto-updated Oct 8, 2026
Fix named in the CVE record. Sources: github.
GitHub advisoryMentions a patch (unverified)

Email Parameter Fallback Leads To Account Takeover Within Apple OAuth · Advisory · RocketChat/Rocket.Chat · GitHub

https://github.com/RocketChat/Rocket.Chat/security/advisories/GHSA-wx3c-76rf-wpwf

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 35× 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 157 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 57 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  2. 2026-10-14 01:56 UTCEG score recompute
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  4. 2026-10-12 22:12 UTCEG score recompute
  5. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  6. 2026-10-12 15:55 UTCEG score recompute
  7. 2026-10-11 19:38 UTCEG score recompute
  8. 2026-10-11 16:54 UTCEG score recompute
  9. 2026-10-11 14:16 UTCEG score recompute
  10. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  11. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  13. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  19. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  20. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  21. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  22. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  23. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  24. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  25. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
Show 75 more
  1. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  2. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  3. 2026-09-23 09:49 UTCEG score recompute
  4. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  5. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  6. 2026-09-18 07:46 UTCEG score recompute
  7. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  8. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  9. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  10. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  11. 2026-09-14 01:31 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  13. 2026-09-12 16:05 UTCEG score recompute
  14. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  15. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  16. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  17. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  18. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  19. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  20. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  21. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  22. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  23. 2026-08-30 19:49 UTCEG score recompute
  24. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  25. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  26. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  27. 2026-08-28 02:58 UTCEG score recompute
  28. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  29. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  30. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  31. 2026-08-24 21:53 UTCEG score recompute
  32. 2026-08-24 13:18 UTCEG score recompute
  33. 2026-08-23 02:26 UTCEG score recompute
  34. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  35. 2026-08-22 01:05 UTCEG score recompute
  36. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  37. 2026-08-20 23:48 UTCEG score recompute
  38. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  39. 2026-08-20 07:13 UTCEG score recompute
  40. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  41. 2026-08-19 01:39 UTCEG score recompute
  42. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  43. 2026-08-17 15:06 UTCEG score recompute
  44. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  45. 2026-08-16 15:32 UTCEG score recompute
  46. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  47. 2026-08-16 04:09 UTCEG score recompute
  48. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  49. 2026-08-15 02:16 UTCEG score recompute
  50. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  51. 2026-08-13 23:40 UTCEG score recompute
  52. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  53. 2026-08-12 16:40 UTCEG score recompute
  54. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  55. 2026-08-11 13:49 UTCEG score recompute
  56. 2026-08-11 02:25 UTCEG score recompute
  57. 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  58. 2026-08-09 16:13 UTCEG score recompute
  59. 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  60. 2026-08-08 17:26 UTCEG score recompute
  61. 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  62. 2026-08-07 18:40 UTCEG score recompute
  63. 2026-08-06 16:00 UTCEG score recompute
  64. 2026-08-06 13:47 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  65. 2026-08-05 21:02 UTCEG score recompute
  66. 2026-08-05 19:17 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  67. 2026-08-04 18:57 UTCEG score recompute
  68. 2026-08-04 15:10 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  69. 2026-08-04 15:09 UTCEG score recompute
  70. 2026-08-04 10:39 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  71. 2026-08-03 14:00 UTCEG score recompute
  72. 2026-08-03 10:36 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  73. 2026-08-02 02:39 UTCEG score recompute
  74. 2026-08-02 02:27 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  75. 2026-08-01 07:39 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55666?
CVE-2026-55666 is a critical-severity vulnerability; its CVE record was published on June 24, 2026. Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13, in apps/meteor/app/apple/server/loginHandler.ts, handleIdentityToken parses a JWT issued by Apple during the OAuth flow. The try block checks for an…
When was the CVE record for CVE-2026-55666 published?
The CVE record for CVE-2026-55666 was published on June 24, 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 June 29, 2026; the record at its source may have been updated since.
Is CVE-2026-55666 actively exploited?
CVE-2026-55666 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55666?
CVE-2026-55666 has a CVSS base score of 9.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55666?
The CVE record for CVE-2026-55666 names the fix: "This vulnerability is fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13."

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-55666

Explore →

Is Your Infrastructure Affected by CVE-2026-55666?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs