CVE-2026-8809

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 2026-05-29. A secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-33165 (ENISA EUVD) · GHSA-jvvq-c627-79xm (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan mitigationNo fix is confirmed yet: check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule 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: 0.8%CVSS: 9.8Exploit: None knownExposed services: Not assessed

No fix is confirmed yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for the fix.

The CVE record's CNA (Wordfence) lists hwk-fr Advanced Custom Fields: Extended versions up to and including 0.9.2.5 as affected. No release containing a fix is confirmed on record.

The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to Privilege Escalation via Validation Bypass in all versions up to and including 0.9.2.5. The vulnerability exists due to the after_validate_save_post() function unconditionally trusting the attacker-controlled _acf_post_id POST parameter — with no authentication or integrity verification — to select a cleanup branch that silently discards all validation errors not prefixed with acfe:. This makes it possible for unauthenticated attackers to suppress both the role allow-list validation error added by acfe_field_user_roles::validate_front_value() and the administrator-role capability guard error added by acfe_module_form_action_user::validate_action(), causing wp_insert_user() to execute with an attacker-supplied administrator role argument and resulting in the creation of a new administrator-level user account. Exploitation requires the target site to expose a public ACFE frontend form configured with a Create User action that maps a role field.

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 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.
Exploitation0.8% × 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: No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
0.8%
EPSS %ILE
57th
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
0.8% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-11). 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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.Each input and its source, and whom BOD 26-04 binds: 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).

No fix is confirmed yet. Check the vendor's advisory for a fixed release; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule 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.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

The score's inputs: 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

May 28, 2026

Last Modified

July 21, 2026

Vendor Advisories for CVE-2026-8809(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 14× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 486 rows 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 386 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:35 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  2. 2026-11-12 16:24 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-11-11 17:18 UTCEchelonGraph re-scored
  4. 2026-11-11 17:18 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-11-11 16:41 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  6. 2026-11-10 18:12 UTCEchelonGraph re-scored
  7. 2026-11-10 18:12 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-11-10 16:46 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  9. 2026-11-09 19:07 UTCEchelonGraph re-scored
  10. 2026-11-09 19:07 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  12. 2026-11-08 20:00 UTCEchelonGraph re-scored
  13. 2026-11-08 20:00 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-11-08 16:41 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  15. 2026-11-07 20:55 UTCEchelonGraph re-scored
  16. 2026-11-07 20:55 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  17. 2026-11-07 16:40 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  18. 2026-11-06 21:51 UTCEchelonGraph re-scored
  19. 2026-11-06 21:51 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  21. 2026-11-05 22:46 UTCEchelonGraph re-scored
  22. 2026-11-05 22:46 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-11-05 16:39 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  24. 2026-11-04 23:42 UTCEchelonGraph re-scored
  25. 2026-11-04 23:42 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
Show 75 more
  1. 2026-11-04 16:37 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  2. 2026-11-04 00:37 UTCEchelonGraph re-scored
  3. 2026-11-04 00:37 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  5. 2026-11-03 01:32 UTCEchelonGraph re-scored
  6. 2026-11-03 01:32 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  8. 2026-11-02 02:27 UTCEchelonGraph re-scored
  9. 2026-11-02 02:27 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  10. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  11. 2026-11-01 03:23 UTCEchelonGraph re-scored
  12. 2026-11-01 03:23 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  14. 2026-10-31 04:18 UTCEchelonGraph re-scored
  15. 2026-10-31 04:18 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  17. 2026-10-30 05:10 UTCEchelonGraph re-scored
  18. 2026-10-30 05:10 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  19. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  20. 2026-10-29 06:07 UTCEchelonGraph re-scored
  21. 2026-10-29 06:07 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  22. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  23. 2026-10-28 07:02 UTCEchelonGraph re-scored
  24. 2026-10-28 07:02 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  26. 2026-10-27 07:58 UTCEchelonGraph re-scored
  27. 2026-10-27 07:58 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  29. 2026-10-26 06:23 UTCEchelonGraph re-scored
  30. 2026-10-26 06:23 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  31. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  32. 2026-10-25 13:53 UTCEchelonGraph re-scored
  33. 2026-10-25 07:19 UTCEchelonGraph re-scored
  34. 2026-10-25 07:19 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  35. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  36. 2026-10-24 08:14 UTCEchelonGraph re-scored
  37. 2026-10-24 08:14 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  38. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  39. 2026-10-23 09:09 UTCEchelonGraph re-scored
  40. 2026-10-23 09:09 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  41. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  42. 2026-10-22 10:03 UTCEchelonGraph re-scored
  43. 2026-10-22 10:02 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  44. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  45. 2026-10-21 10:56 UTCEchelonGraph re-scored
  46. 2026-10-21 10:56 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  47. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  48. 2026-10-20 11:51 UTCEchelonGraph re-scored
  49. 2026-10-20 11:51 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  50. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  51. 2026-10-19 12:46 UTCEchelonGraph re-scored
  52. 2026-10-19 12:46 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  54. 2026-10-18 11:10 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-10-18 03:03 UTCEchelonGraph re-scored
  56. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  57. 2026-10-17 12:06 UTCEchelonGraph re-scored
  58. 2026-10-17 12:06 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  59. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  60. 2026-10-16 12:58 UTCEchelonGraph re-scored
  61. 2026-10-16 12:58 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  63. 2026-10-15 13:52 UTCEchelonGraph re-scored
  64. 2026-10-15 13:51 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  66. 2026-10-14 08:46 UTCEchelonGraph re-scored
  67. 2026-10-14 08:45 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  68. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  69. 2026-10-13 04:16 UTCEchelonGraph re-scored
  70. 2026-10-13 04:16 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  71. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  72. 2026-10-12 14:49 UTCEchelonGraph re-scored
  73. 2026-10-12 05:10 UTCGHSA enrichmentGHSA-jvvq-c627-79xm · GitHub severity CRITICAL · GitHub CVSS 9.8
  74. 2026-10-11 19:15 UTCEchelonGraph re-scored
  75. 2026-10-11 16:32 UTCEchelonGraph re-scored

Frequently asked(5)

What is CVE-2026-8809?
CVE-2026-8809 is a critical-severity vulnerability; its CVE record was published on May 28, 2026. The Advanced Custom Fields: Extended plugin for WordPress is vulnerable to Privilege Escalation via Validation Bypass in all versions up to and including 0.9.2.5. The vulnerability exists due to the after_validate_save_post() function unconditionally trusting the attacker-controlled _acf_post_id…
When was the CVE record for CVE-2026-8809 published?
The CVE record for CVE-2026-8809 was published on May 28, 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 21, 2026; the record at its source may have been updated since.
Is CVE-2026-8809 actively exploited?
CVE-2026-8809 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (57th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-8809?
CVE-2026-8809 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-8809?
No fix for CVE-2026-8809 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (Wordfence) lists hwk-fr Advanced Custom Fields: Extended versions up to and including 0.9.2.5 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-8809 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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