TI-2026-21071 Aliases CVE-2026-26067 GHSA-3888-q23f-x7qh

October: Safe Mode Bypass via CSS Preprocessor Compilers

LOW 22CWE-184Published 2026-04-21 · Updated 2026-04-21

Key facts

Attack vector: Network
Privileges required: High
User interaction: None
Attack complexity: Low
Impact type: Security bypass, Information disclosure
Confidentiality · integrity · availability: High · None · None
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863 and CWE-200.

Summary

October is a Content Management System (CMS) and web platform. Prior to 3.7.14 and 4.1.10, a server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft .less, .sass, or .scss files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with cms.safe_mode enabled. This vulnerability is fixed in 3.7.14 and 4.1.10.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00246 15th percentileScored 2026-11-07

Fix Fixed october (octobercms): 4.1.10, 3.7.14october/system (Packagist): 3.7.14, 4.1.10

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
October CMS	october	4.0.0 to before 4.1.10; before 3.7.14	4.1.10, 3.7.14	Patch available	CNA
—	october/system (Packagist)	before 3.7.14	3.7.14	Patch available	GHSA-3888-q23f-x7qh
—	october/system (Packagist)	4.0.0 to before 4.1.10	4.1.10	Patch available	GHSA-3888-q23f-x7qh

october VendorOctober CMS Affected 4.0.0 to before 4.1.10; before 3.7.14 Fixed in 4.1.10, 3.7.14 Patch available CNA
october/system (Packagist) Vendor— Affected before 3.7.14 Fixed in 3.7.14 Patch available GHSA-3888-q23f-x7qh
october/system (Packagist) Vendor— Affected 4.0.0 to before 4.1.10 Fixed in 4.1.10 Patch available GHSA-3888-q23f-x7qh

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:octobercms:october::::::::	—	—	October CMS

cpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:* Versions — — ·October CMS

Remediation

Fix · CNA october (octobercms) Fixed in 4.1.10, 3.7.14
Fix · GHSA-3888-q23f-x7qh october/system (Packagist) Fixed in 3.7.14 Advisory →
Fix · GHSA-3888-q23f-x7qh october/system (Packagist) Fixed in 4.1.10 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2026-26067
2026-10-03 Alias added: GHSA-3888-q23f-x7qh

References

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-26067

Other 2

TI-2021-12316 Account Takeover in Octobercms KEVCVSS 3.1CRITICAL 9.1
TI-2021-12318 Arbitrary code execution in october/system CVSS 3.1HIGH 8.8
TI-2017-14456 October CMS build 412 is vulnerable to PHP code execution in the file upload… CVSS 3.0HIGH 7.2
TI-2023-23545 A Cross-Site Scripting (XSS) vulnerability in installation of October v.3.4.16 allows an… CVSS 3.1MEDIUM 5.4
TI-2023-19223 An arbitrary file upload vulnerability in October CMS v3.4.4 allows attackers to execute… CVSS 3.1MEDIUM 5.4
TI-2024-30847 October 3.6.30 allows an authenticated admin account to upload a PDF file containing… CVSS 3.1MEDIUM 4.7

See all 63 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences