Security readout for executives and security teams
Plain-English summary
October CMS installations relying on Safe Mode could still let a highly privileged backend user execute PHP through crafted Twig content. The issue matters when those users are trusted to edit CMS templates or pages, but not trusted to run PHP. Vendor sources say it was patched in Build 470 and v1.1.1.
Executive priority
Treat this as a targeted privilege-bound code execution risk, not an internet-wide emergency. Prioritize if October CMS is used in production with delegated content administrators who should not run PHP. Patch and review privileged CMS accounts promptly.
Technical view
CVE-2020-26231 is a bypass of the CVE-2020-15247 fix in October CMS. An authenticated backend user with cms.manage_pages, cms.manage_layouts, or cms.manage_partials could escape the Twig sandbox when cms.enableSafeMode was enabled, leading to arbitrary PHP execution. The CVE lists October CMS 1.0.469 as affected.
Likely exposure
Exposure is likely limited to self-hosted October CMS deployments on the affected build where backend users have page, layout, or partial management permissions and Safe Mode is expected to prevent PHP execution. Environments that already trust those users to write PHP are less affected by the stated security boundary.
Exploitation context
The source bundle does not show KEV listing or cited evidence of active exploitation. Exploitation requires an authenticated backend user with high CMS editing privileges and user interaction per CVSS. The main risk is insider, compromised account, or delegated content-admin access becoming code execution.
Researcher notes
Evidence is strongest for October CMS 1.0.469 and vendor-patched releases Build 470 and v1.1.1. The issue is specifically a Safe Mode/Twig sandbox boundary failure. Do not assume unauthenticated exposure or active exploitation from the provided sources.
Mitigation direction
- Upgrade October CMS to Build 470, v1.1.1, or later vendor-supported releases.
- Review backend users with cms.manage_pages, cms.manage_layouts, or cms.manage_partials permissions.
- Remove those permissions from users not trusted to execute PHP.
- Confirm cms.enableSafeMode assumptions against current vendor guidance.
- Prioritize credential hygiene for privileged October CMS backend accounts.
Validation and detection
- Inventory October CMS deployments and identify exact installed versions.
- Flag installations running October CMS 1.0.469 as affected per CVE data.
- Check whether cms.enableSafeMode is enabled in production.
- List backend users holding page, layout, or partial management permissions.
- Confirm the vendor patch or later release is deployed.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-862: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2020-26231 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L1.13.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.2MediumVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/octobercms/october/security/advisories/GHSA-r89v-cgv7-3jhxCVE reference · x_refsource_CONFIRM
- https://github.com/octobercms/october/commit/d34fb8ab51108495a9a651b841202d935f4e12f7CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Authorization
Missing Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.