GHSA-xhfv-7758-r9hx

Suggest an improvement
Source
https://github.com/advisories/GHSA-xhfv-7758-r9hx
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-xhfv-7758-r9hx/GHSA-xhfv-7758-r9hx.json
JSON Data
https://api.test.osv.dev/v1/vulns/GHSA-xhfv-7758-r9hx
Aliases
Published
2026-09-17T20:45:15Z
Modified
2026-09-17T21:00:04Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H CVSS Calculator
  • 7.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
Grav: Missing admin.super guard on core group blueprint access field allows admin.users operator to escalate to super-admin
Details

Summary

The core Flex group blueprint system/blueprints/user/group.yaml (access field, lines 48-55) omits the security@: admin.super field guard that its sibling account blueprint carries (account.yaml:131/138/150, added by the CVE-2026-42613 fix). A delegated non-super operator holding admin.users.update can therefore save a group whose access map contains admin.super: true, which UserGroupObject::authorize then grants to every member of that group, a full privilege escalation to super-admin (scheduler/cron RCE, Twig eval). This is a distinct file, sink, and fix from all four related advisories.

Root Cause

The CVE-2026-42613 fix protected the account access/groups fields with a blueprint-level security@: admin.super gate, which Blueprint::dynamicSecurity() (system/src/Grav/Common/Data/Blueprint.php:644-662) uses to mark a field validate.ignore=true for non-super users so BlueprintSchema::filterArray() (BlueprintSchema.php:263-311) drops it. The functionally-identical group access field, a permission map granted to every member of the group, is declared in system/blueprints/user/group.yaml:48-55 with check_authorize: false and NO security@ guard. check_authorize has ZERO PHP enforcement (grep -rn check_authorize across the repo returns 0 PHP consumers; only two YAML blueprints reference it), so security@ is the sole real control. Because the group access field lacks security@, dynamicSecurity never flags it, filterArray retains it, and Validation::filterArray (type: array, value_type: bool) passes the nested admin.super:true leaf through. The core save path (FlexObject::update() then Framework/Flex/FlexObject.php:683 $blueprint->filter($data,true,true) then save()) persists it to user://config/groups.yaml.

Impact

A delegated admin.users operator (strictly below admin.super) escalates to super-admin, gaining the admin panel, the scheduler (cron to RCE) and Twig evaluation. Full read/write/DoS (C:H/I:H/A:H). Even absent self-escalation, arbitrary rewrite of ANY group's ACL is itself a full escalation primitive.

Proof of Concept

As a non-super admin.users operator who is a member of group ops:

POST /admin/accounts/groups/ops   (or groups.json task:save)
data[access][admin][super]=1

user/config/groups.yaml gains ops: { access: { admin: { super: true } } }, so the operator is super-admin on the next request.

Attack Chain

  1. Entry: authenticated delegated admin (admin.users.update, no admin.super) POSTs the group-edit form for a group they belong to (or a new group), body access[admin][super]=true. Guard: FlexAuthorizeTrait::isAuthorizedAction to admin.users.update. Bypass proof: user-groups.yaml exposes groups at admin.users:crudl; operator legitimately holds update.
  2. Check (field guard): Blueprint::dynamicSecurity marks validate.ignore only for security@ fields. Guard: none on group access (no security@). Bypass proof: group.yaml:48-55 has no security@; git log -S 'security@' -- system/blueprints/user/group.yaml is empty.
  3. Filter: BlueprintSchema::filterArray retains the non-ignored field; Validation::filterArray (value_type: bool) passes admin.super:true through. Bypass proof: field not flagged ignore/disabled; nested bool leaf preserved.
  4. Sink (persist): FlexObject::update then filter then save writes to user://config/groups.yaml. Guard: none. Bypass proof: value already survived steps 2/3; storage performs no ACL filtering.
  5. Impact: any member request triggers UserGroupObject::authorize('admin.super') (.../UserGroups/UserGroupObject.php:75) returning true, so the member is super-admin, enabling scheduler/Twig RCE.

Bypass Evidence

  • system/blueprints/user/group.yaml:48-55: access block with check_authorize: false, no security@ (confirmed live on tag 2.0.12).
  • git log -S 'security@' -- system/blueprints/user/group.yaml is empty (guard never existed; a permanent gap, not a regression).
  • git log 2.0.12..HEAD -- system/blueprints/user/group.yaml is empty (no post-release fix).
  • grep -rn check_authorize (whole repo) returns 0 PHP hits (guard unenforced in PHP).
  • grep -rn "typePermissions|filterPermissions" system/src/Grav/Common/Data returns 0 (permissions map falls through to array-bool filtering that keeps nested keys).
  • Guard asymmetry: account.yaml:131/138/150 carry security@: admin.super; group.yaml carries none. GHSA-h33v-82r9-v8pm's own text confirms the blueprint security@ gate is the sole Flex-backend strip for these keys.

Affected Versions

<= 2.0.12 (latest release; the guard never existed on group.yaml, so all 2.x are affected). The missing guard and the strip logic are both in core getgrav/grav; the group-edit UI is provided by the flex-objects/admin plugin, but the fix belongs in core.

Suggested Fix

Add security@: admin.super to the access field in system/blueprints/user/group.yaml (mirroring account.yaml), and/or enforce a super-only strip on group ACL saves in core so all callers are covered.

Reported by zx (Jace) — GitHub: @manus-use

Database specific 
{
    "cwe_ids":  [
        "CWE-269",
        "CWE-862"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-09-17T20:45:15Z",
    "nvd_published_at":  null,
    "severity":  "HIGH"
}
References

Affected packages

Packagist / getgrav/grav

Package

Name
getgrav/grav
Purl
pkg:composer/getgrav/grav

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.0.14

Affected versions

0.*
0.8.0
0.9.0
0.9.1
0.9.2
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
0.9.10
0.9.11
0.9.12
0.9.13
0.9.14
0.9.15
0.9.16
0.9.17
0.9.18
0.9.19
0.9.20
0.9.21
0.9.22
0.9.23
0.9.24
0.9.25
0.9.26
0.9.27
0.9.28
0.9.29
0.9.30
0.9.31
0.9.32
0.9.33
0.9.34
0.9.35
0.9.36
0.9.37
0.9.38
0.9.39
0.9.40
0.9.41
0.9.42
0.9.43
0.9.44
0.9.45
1.*
1.0.0-rc.1
1.0.0-rc.2
1.0.0-rc.3
1.0.0-rc.4
1.0.0-rc.5
1.0.0-rc.6
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.0.5
1.0.6
1.0.7
1.0.8
1.0.9
1.0.10
1.1.0-beta.1
1.1.0-beta.2
1.1.0-beta.3
1.1.0-beta.4
1.1.0-beta.5
1.1.0-rc.1
1.1.0-rc.2
1.1.0-rc.3
1.1.0
1.1.1
1.1.2
1.1.3
1.1.4
1.1.5
1.1.6
1.1.7
1.1.8
1.1.9-rc.1
1.1.9-rc.2
1.1.9-rc.3
1.1.9
1.1.10
1.1.11
1.1.12
1.1.13
1.1.14
1.1.15
1.1.16
1.1.17
1.2.0-rc.1
1.2.0-rc.2
1.2.0-rc.3
1.2.0
1.2.1
1.2.2
1.2.3
1.2.4
1.3.0-rc.1
1.3.0-rc.2
1.3.0-rc.3
1.3.0-rc.4
1.3.0-rc.5
1.3.0
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.8
1.3.9
1.3.10
1.4.0-beta.1
1.4.0-beta.2
1.4.0-beta.3
1.4.0-rc.1
1.4.0-rc.2
1.4.0
1.4.1
1.4.2
1.4.3
1.4.4
1.4.5
1.4.6
1.4.7
1.4.8
1.5.0-beta.1
1.5.0-beta.2
1.5.0-rc.1
1.5.0
1.5.1
1.5.2
1.5.3
1.5.4
1.5.5
1.5.6
1.5.7
1.5.8
1.5.9
1.5.10
1.6.0-beta.1
1.6.0-beta.2
1.6.0-beta.3
1.6.0-beta.4
1.6.0-beta.5
1.6.0-beta.6
1.6.0-beta.7
1.6.0-beta.8
1.6.0-rc.1
1.6.0-rc.2
1.6.0-rc.3
1.6.0-rc.4
1.6.0
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.6
1.6.7
1.6.8
1.6.9
1.6.10
1.6.11
1.6.12
1.6.13
1.6.14
1.6.15
1.6.16
1.6.17
1.6.18
1.6.19
1.6.20
1.6.21
1.6.22
1.6.23
1.6.24
1.6.25
1.6.26
1.6.27
1.6.28
1.6.29
1.6.30
1.6.31
1.7.0-beta.1
1.7.0-beta.2
1.7.0-beta.3
1.7.0-beta.4
1.7.0-beta.5
1.7.0-beta.6
1.7.0-beta.7
1.7.0-beta.8
1.7.0-beta.9
1.7.0-beta.10
1.7.0-rc.1
1.7.0-rc.2
1.7.0-rc.3
1.7.0-rc.4
1.7.0-rc.5
1.7.0-rc.6
1.7.0-rc.7
1.7.0-rc.8
1.7.0-rc.9
1.7.0-rc.10
1.7.0-rc.11
1.7.0-rc.12
1.7.0-rc.13
1.7.0-rc.14
1.7.0-rc.15
1.7.0-rc.16
1.7.0-rc.17
1.7.0-rc.18
1.7.0-rc.19
1.7.0-rc.20
1.7.0
1.7.1
1.7.3
1.7.4
1.7.5
1.7.6
1.7.7
1.7.8
1.7.9
1.7.10
1.7.12
1.7.13
1.7.14
1.7.15
1.7.16
1.7.17
1.7.18
1.7.19
1.7.20
1.7.21
1.7.22
1.7.23
1.7.24
1.7.25
1.7.26
1.7.26.1
1.7.27
1.7.27.1
1.7.28
1.7.29
1.7.29.1
1.7.30
1.7.31
1.7.32
1.7.33
1.7.34
1.7.35
1.7.36
1.7.37
1.7.37.1
1.7.38
1.7.39
1.7.39.1
1.7.39.2
1.7.39.3
1.7.39.4
1.7.40
1.7.41
1.7.41.1
1.7.41.2
1.7.42
1.7.42.1
1.7.42.2
1.7.42.3
1.7.43
1.7.44
1.7.45
1.7.46
1.7.47
1.7.48
1.7.49
1.7.49.1
1.7.49.2
1.7.49.3
1.7.49.4
1.7.49.5
1.7.51
1.7.52
1.7.53
1.7.53.1
1.7.53.2
1.7.53.3
1.8.0-beta.1
1.8.0-beta.2
1.8.0-beta.3
1.8.0-beta.4
1.8.0-beta.5
1.8.0-beta.6
1.8.0-beta.7
1.8.0-beta.8
1.8.0-beta.9
1.8.0-beta.10
1.8.0-beta.11
1.8.0-beta.12
1.8.0-beta.13
1.8.0-beta.14
1.8.0-beta.15
1.8.0-beta.16
1.8.0-beta.17
1.8.0-beta.18
1.8.0-beta.19
1.8.0-beta.20
1.8.0-beta.21
1.8.0-beta.22
1.8.0-beta.23
1.8.0-beta.24
1.8.0-beta.25
1.8.0-beta.26
1.8.0-beta.27
1.8.0-beta.28
1.8.0-beta.29
2.*
2.0.0-beta.1
2.0.0-beta.2
2.0.0-beta.3
2.0.0-beta.4
2.0.0-rc.1
2.0.0-rc.2
2.0.0-rc.3
2.0.0-rc.4
2.0.0-rc.5
2.0.0-rc.6
2.0.0-rc.7
2.0.0-rc.8
2.0.0-rc.9
2.0.0-rc.10
2.0.0
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
2.0.6
2.0.7
2.0.8
2.0.9
2.0.10
2.0.11
2.0.12
2.0.13

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-xhfv-7758-r9hx/GHSA-xhfv-7758-r9hx.json"