CVE-2026-53421

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 2026-07-20. 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

Also known asEUVD-2026-45958 (ENISA EUVD) · GHSA-c7pj-2f8j-jc8m (GitHub Security Advisories)Source: ENISA EUVD

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: 1.1%CVSS: 9.8Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

Improper Isolation or Compartmentalization vulnerability in Apache Syncope.

An administrator with adequate entitlements can achieve remote code execution through the connector subsystem by relying on scripted connectors' (REST and SQL) capability to run Groovy scripts.

This issue affects Apache Syncope: from 3.0.0-M0 through 3.0.16, from 4.0.0-M0 Through 4.0.6, from 4.1.0-M0 through 4.1.1.

Users are recommended to upgrade to version 4.0.7 / 4.1.2, which fix this issue by hardening the Groovy security sandbox.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
60
EG Risk 60/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.1% × 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
1.1%
EPSS %ILE
66th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
1.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

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 20, 2026

Last Modified

October 24, 2026

Advisory Details (2)

Auto-updated Oct 26, 2026
Fix named in the CVE record.
Web page

oss-security - CVE-2026-53421: Apache Syncope: Remote Code Execution via Scripted Connector

http://www.openwall.com/lists/oss-security/2026/07/20/7

Vendor Advisories for CVE-2026-53421(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 21× in last 7d / 76× 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 514 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 414 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  2. 2026-10-29 15:40 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-28 16:59 UTCEG score recompute
  4. 2026-10-28 16:59 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  6. 2026-10-27 18:23 UTCEG score recompute
  7. 2026-10-27 18:23 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-27 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  9. 2026-10-26 19:55 UTCEG score recompute
  10. 2026-10-26 19:55 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  12. 2026-10-25 19:12 UTCEG score recompute
  13. 2026-10-25 19:12 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-10-25 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  15. 2026-10-25 14:20 UTCEG score recompute
  16. 2026-10-24 20:26 UTCEG score recompute
  17. 2026-10-24 20:26 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-24 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  19. 2026-10-24 00:42 UTCEG score recompute
  20. 2026-10-24 00:42 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-23 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  22. 2026-10-23 02:14 UTCEG score recompute
  23. 2026-10-23 02:14 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-22 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  25. 2026-10-22 03:43 UTCEG score recompute
Show 75 more
  1. 2026-10-22 03:43 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  2. 2026-10-21 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  3. 2026-10-21 05:16 UTCEG score recompute
  4. 2026-10-21 05:15 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-20 16:33 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  6. 2026-10-20 06:47 UTCEG score recompute
  7. 2026-10-20 06:47 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-19 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  9. 2026-10-19 08:17 UTCEG score recompute
  10. 2026-10-19 08:17 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-18 16:32 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  12. 2026-10-18 09:48 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-18 03:31 UTCEG score recompute
  14. 2026-10-17 16:34 UTCEPSS rescoreEPSS 1.1% · 66th percentile
  15. 2026-10-17 11:19 UTCEG score recompute
  16. 2026-10-17 11:19 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-10-16 16:42 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  18. 2026-10-16 12:48 UTCEG score recompute
  19. 2026-10-16 12:48 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-10-15 16:32 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  21. 2026-10-15 14:13 UTCEG score recompute
  22. 2026-10-15 14:13 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-10-14 16:33 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  24. 2026-10-14 08:58 UTCEG score recompute
  25. 2026-10-14 08:58 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  26. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  27. 2026-10-13 05:30 UTCEG score recompute
  28. 2026-10-13 05:30 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  29. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  30. 2026-10-12 15:57 UTCEG score recompute
  31. 2026-10-12 07:02 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  32. 2026-10-11 19:40 UTCEG score recompute
  33. 2026-10-11 16:55 UTCEG score recompute
  34. 2026-10-11 14:19 UTCEG score recompute
  35. 2026-10-11 13:49 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  36. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  37. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  38. 2026-10-08 17:12 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  39. 2026-10-07 23:48 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  40. 2026-10-06 15:18 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  41. 2026-10-05 17:43 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  42. 2026-10-04 23:22 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  43. 2026-10-04 14:57 UTCEG score recompute
  44. 2026-10-04 14:57 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-03 14:26 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  46. 2026-10-02 17:56 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  47. 2026-10-01 19:50 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  48. 2026-10-01 12:32 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-10-01 07:45 UTCEG score recompute
  50. 2026-10-01 07:45 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  51. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  52. 2026-09-29 15:22 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  53. 2026-09-28 13:51 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  54. 2026-09-28 10:54 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-09-28 06:23 UTCEG score recompute
  56. 2026-09-28 06:23 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-09-27 13:48 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  58. 2026-09-26 15:59 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  59. 2026-09-24 14:04 UTCEPSS rescoreEPSS 1.1% · 65th percentile
  60. 2026-09-24 13:10 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-09-24 08:21 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-09-24 03:29 UTCEG score recompute
  63. 2026-09-24 03:29 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  64. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  65. 2026-09-23 10:57 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  66. 2026-09-23 06:06 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  67. 2026-09-23 01:43 UTCEG score recompute
  68. 2026-09-23 01:43 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  69. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  70. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 50th percentile
  71. 2026-09-18 08:48 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-09-18 03:58 UTCEG score recompute
  73. 2026-09-18 03:58 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-09-17 09:54 UTCGHSA enrichmentGHSA-c7pj-2f8j-jc8m · GitHub severity CRITICAL · GitHub CVSS 9.8
  75. 2026-09-17 05:15 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-53421?
CVE-2026-53421 is a critical-severity vulnerability; its CVE record was published on July 20, 2026. Improper Isolation or Compartmentalization vulnerability in Apache Syncope. An administrator with adequate entitlements can achieve remote code execution through the connector subsystem by relying on scripted connectors' (REST and SQL) capability to run Groovy scripts. This issue affects Apache…
When was the CVE record for CVE-2026-53421 published?
The CVE record for CVE-2026-53421 was published on July 20, 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 October 24, 2026; the record at its source may have been updated since.
Is CVE-2026-53421 actively exploited?
CVE-2026-53421 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% probability of exploitation in the next 30 days (66th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-53421?
CVE-2026-53421 has a CVSS v3.1 base score of 9.8 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-53421?
The CVE record for CVE-2026-53421 names the fix: "Users are recommended to upgrade to version 4.0.7 / 4.1.2, which fix this issue by hardening the Groovy security sandbox." The vendor advisories EchelonGraph has for CVE-2026-53421 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-53421

Explore →

Is Your Infrastructure Affected by CVE-2026-53421?

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