CVE-2026-27591

CRITICALPre-NVD 9.99.9
EchelonGraph scoreMEDIUM confidence

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

Score 9.9 from GitHub Security Advisory (severity: CRITICAL) published 2026-03-12. A secondary CVSS source baseline 9.9; sources differ by 0.0.

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

Also known asEUVD-2026-11406 (ENISA EUVD) · GHSA-pgpf-m8m4-6cg6 (GitHub Security Advisories)Source: ENISA EUVD

9.9EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.8%CVSS: 9.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their account through specially crafted requests to the backend while logged in. To actively exploit this security issue, an attacker would need access to the Backend with a user account with any level of access. This vulnerability is fixed in 1.0.477, 1.1.12, and 1.2.12.

CVSS v3
9.9
EG Score
9.9CRITICALmedium confidence
EG Risk
45
EG Risk 45/100

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)
Severity99% × 45%
Impact severity (EG Severity): CVSS 9.9 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.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (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: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.8%
EPSS %ILE
56th
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 (9.9): severity, escalated by confirmed exploitation. This CVE's 9.9 is its impact severity (EG Severity), not escalated.

EG Severity
9.9 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; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.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; 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). 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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

March 11, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Nov 6, 2026
Patch available. Sources: github.
Web page

v1.2.12 - Winter CMS Release Notes | Winter CMS

https://wintercms.com/releases/v1.2.12
Web page

v1.1.12 - Winter CMS Release Notes | Winter CMS

https://wintercms.com/releases/v1.1.12
Web page

v1.0.477 - Winter CMS Release Notes | Winter CMS

https://wintercms.com/releases/v1.0.477
GitHub advisoryMentions a patch (unverified)

Privilege escalation by authenticated backend users · Advisory · wintercms/winter · GitHub

https://github.com/wintercms/winter/security/advisories/GHSA-pgpf-m8m4-6cg6

Vendor Advisories for CVE-2026-27591(1)

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

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
composerwinter/wn-backend-module @ 1.2.12 (fixes >= 1.2.0, < 1.2.12)—ghsa
composerwinter/wn-backend-module @ 1.0.477 (fixes < 1.0.477)—ghsa
composerwinter/wn-backend-module @ 1.1.12 (fixes >= 1.1.0, < 1.1.12)—ghsa

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

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFix by version rangeDependents
winter/wn-backend-modulev1.0.473, v1.0.474, v1.0.475
  • 1.2.0 up to 1.2.12: fixed in 1.2.12
  • 1.1.0 up to 1.1.12: fixed in 1.1.12
  • every version up to 1.0.477: fixed in 1.0.477
—

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 43× 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 160 rows on record for this CVE, as 99 entries (1 repeat merged).

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. 1 repeat row among the latest 100 is merged into the row it repeats. The 60 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  2. 2026-11-12 12:17 UTCEchelonGraph re-scored
  3. 2026-11-12 12:17 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  4. 2026-11-11 16:39 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  5. 2026-11-11 11:20 UTCEchelonGraph re-scored
  6. 2026-11-11 11:20 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  7. 2026-11-10 16:43 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  8. 2026-11-10 10:23 UTCEchelonGraph re-scored
  9. 2026-11-10 10:23 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  10. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  11. 2026-11-09 09:25 UTCEchelonGraph re-scored
  12. 2026-11-09 09:25 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  13. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  14. 2026-11-08 08:28 UTCEchelonGraph re-scored
  15. 2026-11-08 08:28 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  16. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  17. 2026-11-07 07:31 UTCEchelonGraph re-scored
  18. 2026-11-07 07:31 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  19. 2026-11-06 16:37 UTCEPSS rescoreEPSS 0.8% · 56th percentile
  20. 2026-11-06 06:34 UTCEchelonGraph re-scored
  21. 2026-11-06 06:34 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  22. 2026-11-06 04:25 UTCOSV refresh
  23. 2026-11-05 16:37 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  24. 2026-11-05 05:37 UTCEchelonGraph re-scored
  25. 2026-11-05 05:37 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
Show 74 more
  1. 2026-11-04 16:35 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  2. 2026-11-04 04:40 UTCEchelonGraph re-scored
  3. 2026-11-04 04:40 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  4. 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  5. 2026-11-03 03:43 UTCEchelonGraph re-scored
  6. 2026-11-03 03:43 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  7. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  8. 2026-11-02 02:45 UTCEchelonGraph re-scored
  9. 2026-11-02 02:45 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  10. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  11. 2026-11-01 07:56 UTCEchelonGraph re-scored
  12. 2026-11-01 07:56 UTCGHSA enrichmentGHSA-pgpf-m8m4-6cg6 · GitHub severity CRITICAL · GitHub CVSS 9.9
  13. 2026-11-01 01:48 UTCEchelonGraph re-scored
  14. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  15. 2026-10-31 00:51 UTCEchelonGraph re-scored
  16. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  17. 2026-10-29 23:54 UTCEchelonGraph re-scored
  18. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  19. 2026-10-28 22:57 UTCEchelonGraph re-scored
  20. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  21. 2026-10-27 22:01 UTCEchelonGraph re-scored
  22. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  23. 2026-10-26 21:04 UTCEchelonGraph re-scored
  24. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  25. 2026-10-25 18:03 UTCEchelonGraph re-scored
  26. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  27. 2026-10-25 14:38 UTCEchelonGraph re-scored
  28. 2026-10-24 16:35 UTCEchelonGraph re-scored
  29. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  30. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  31. 2026-10-23 15:37 UTCEchelonGraph re-scored
  32. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  33. 2026-10-22 14:40 UTCEchelonGraph re-scored
  34. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  35. 2026-10-21 13:43 UTCEchelonGraph re-scored
  36. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  37. 2026-10-20 12:46 UTCEchelonGraph re-scored
  38. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  39. 2026-10-19 11:48 UTCEchelonGraph re-scored
  40. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  41. 2026-10-18 03:51 UTCEchelonGraph re-scored
  42. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  43. 2026-10-17 08:45 UTCEchelonGraph re-scored
  44. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  45. 2026-10-16 07:47 UTCEchelonGraph re-scored
  46. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  47. 2026-10-15 06:47 UTCEchelonGraph re-scored
  48. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  49. 2026-10-14 02:30 UTCEchelonGraph re-scored
  50. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  51. 2026-10-12 22:45 UTCEchelonGraph re-scored
  52. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  53. 2026-10-12 16:17 UTCEchelonGraph re-scored
  54. 2026-10-11 19:59 UTCEchelonGraph re-scored
  55. 2026-10-11 17:13 UTCEchelonGraph re-scored
  56. 2026-10-11 14:44 UTCEchelonGraph re-scored
  57. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  58. 2026-10-11 11:47 UTCOSV refresh
  59. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  60. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  61. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  62. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  63. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  64. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  65. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  66. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  67. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  68. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  69. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  70. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  71. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.6% · 44th percentile
  72. 2026-09-22 00:15 UTCOSV refresh
  73. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  74. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 40th percentile

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Frequently asked(5)

What is CVE-2026-27591?
CVE-2026-27591 is a critical-severity vulnerability; its CVE record was published on March 11, 2026. Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.0.477, 1.1.12, and 1.2.12, Winter CMS allowed authenticated backend users to escalate their accounts level of access to the system by modifying the roles / permissions assigned to their…
When was the CVE record for CVE-2026-27591 published?
The CVE record for CVE-2026-27591 was published on March 11, 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 17, 2026; the record at its source may have been updated since.
Is CVE-2026-27591 actively exploited?
CVE-2026-27591 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.8% probability of exploitation in the next 30 days (56th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-27591?
CVE-2026-27591 has a CVSS base score of 9.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-27591?
A fix for CVE-2026-27591 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-27591 are linked in the Vendor Advisories panel on this page.

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