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  4. CVE 2026 81921 in concrete cms 853 to 952 oauth 20 refresh token
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Back to active CVEs
Low · CVSS 2.3CVE-2026-81921

In Concrete CMS 8.5.3 to 9,5,2, OAuth 2.0 Refresh-Token Grant Bypasses Account StatusCVE-2026-81921

Answer in brief

CVE-2026-81921 records a Low severity (CVSS 2.3) vulnerability in In Concrete CMS 8.5.3 to 9,5,2, OAuth 2.0 Refresh-Token Grant Bypasses Account Status. The current sources do not mark it as known exploited. The current feed maps Concrete CMS/Concrete CMS (generic), Concrete CMS/Concrete CMS (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 15, 2026Updated Sep 18, 2026Source checked Oct 31, 2026First seen by HOL Sep 15, 2026Material review Sep 18, 2026
Upstream Advisory

Key facts

Risk
Low · CVSS 2.3
Exploitation
Not marked as known exploited
Affected software
3 mapped packages or products
Fix availability
Not reported

Why this deserves its current priority

CVSS is 2.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Concrete CMS/Concrete CMS (generic), Concrete CMS/Concrete CMS (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Concrete CMS/Concrete CMSgeneric8.5.3Not reported
Concrete CMS/Concrete CMSgeneric>=8.5.3 <=9.5.2Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Concrete CMS/Concrete CMS, Concrete CMS/Concrete CMS.
  2. 2Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

  1. Published upstream

    Sep 15, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Sep 18, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Sep 15, 2026

Sources and claim methodology

  • Source referencedocumentation.concretecms.org
Upstream source description

Concrete CMS 8.5.3 through 9.5.2 enabled the OAuth 2.0 refresh-token grant using the unmodified upstream League grant, which issued new access tokens from a valid refresh token without re-checking the associated account's active status. A user who obtained a refresh token while active could therefore continue to mint valid access tokens after being deactivated or suspended (uIsActive=0), so deactivating an account did not revoke its API access. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L. Thanks sh4d0byss for reporting.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Hustle <= 7.8.14.3 - Missing Authorization to Authenticated (Custom+) ESP Credential Overwrite and Irreversible OAuth Token Deletion via 'hustle_provider_migrate_hubspot' (and sibling migrate_*) AJAX ActionAlso CWE-862
  • Product Filter for WooCommerce by WBW <= 3.4.6 - Missing Authorization to Unauthenticated Information Disclosure via filterSettings[default_query] ParameterAlso CWE-862
  • WP Booking System <= 2.1.0.5 - Missing Authorization to Unauthenticated Arbitrary Calendar Note Deletion via wpbs_calendar_remove_note AJAX ActionAlso CWE-862
  • Premium Packages < 7.2.2 - Unauthenticated Order Total ManipulationAlso CWE-862
  • Mapster WP Maps < 2.0.6 - Unauthenticated Arbitrary Post Modification via save-mapmaker REST RouteAlso CWE-862
  • Popup Builder <= 4.4.5 - Missing Authorization to Unauthenticated Arbitrary Popup Post Trashing via 'post_type' and 'sg_popup_preview_id' ParametersAlso CWE-862

Record context

Vulnerability class
Missing Auth
EPSS
Not reported
CWE IDs
CWE-862
Source
CVE List V5
Source checked
Oct 31, 2026
References
1 linked source
Open source record