TI-2023-12287 Aliases CVE-2023-27577 GHSA-vhm8-wwrf-3gcw

Path Traversal Vulnerability in `LESS` Parser allows reading of sensitive server files in flarum

LOW 31CWE-22Published 2023-03-10 · Updated 2025-02-25

Key facts

Attack vector: Network
Privileges required: High
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: Low · Low · Low
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

Summary

flarum is a forum software package for building communities. In versions prior to 1.7.0 an admin account which has already been compromised by an attacker may use a vulnerability in the `LESS` parser which can be exploited to read sensitive files on the server through the use of path traversal techniques. An attacker can achieve this by providing an absolute path to a sensitive file in the custom `LESS` setting, which the `LESS` parser will then read. For example, an attacker could use the following code to read the contents of the `/etc/passwd` file on a linux machine. The scope of what files are vulnerable will depend on the permissions given to the running flarum process. The vulnerability has been addressed in version `1.7`. Users should upgrade to this version to mitigate the vulnerability. Users unable to upgrade may mitigate the vulnerability by ensuring that their admin accounts are secured with strong passwords and follow other best practices for account security. Additionally, users can limit the exposure of sensitive files on the server by implementing appropriate file permissions and access controls at the operating system level.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00851 58th percentileScored 2026-11-07

Fix Fixed framework (flarum): 1.7.0flarum/core (Packagist): 1.7.0

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
flarum	framework	before 1.7.0	1.7.0	Patch available	CNA
—	flarum/core (Packagist)	before 1.7.0	1.7.0	Patch available	GHSA-vhm8-wwrf-3gcw

framework Vendorflarum Affected before 1.7.0 Fixed in 1.7.0 Patch available CNA
flarum/core (Packagist) Vendor— Affected before 1.7.0 Fixed in 1.7.0 Patch available GHSA-vhm8-wwrf-3gcw

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:flarum:flarum::::::::	before 1.7.0	Vulnerable	flarum

cpe:2.3:a:flarum:flarum:*:*:*:*:*:*:*:* Versions before 1.7.0 Vulnerable ·flarum

Remediation

Fix · CNA framework (flarum) Fixed in 1.7.0
Fix · GHSA-vhm8-wwrf-3gcw flarum/core (Packagist) Fixed in 1.7.0 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2023-27577
2026-10-03 Alias added: GHSA-vhm8-wwrf-3gcw

References

Patch 1

https://github.com/flarum/framework/commit/1761660c98ea5a3e9665fb8e6041d1f2ee62a444

Advisory 2

Other 2

TI-2021-12339 XSS vulnerability with translator CVSS 3.1CRITICAL 10.0
TI-2023-08736 Post mentions can be used to read any post on the forum without access control CVSS 3.1HIGH 7.7
TI-2025-20573 Flarum Vulnerable to Session Hijacking via Authoritative Subdomain Cookie Overwrite CVSS 3.1MEDIUM 6.8
TI-2022-20279 Cross site scripting vulnerability with discussion titles in flarum CVSS 3.1CRITICAL 9.0
TI-2019-09878 Flarum before 0.1.0-beta.9 allows CSRF against all POST endpoints, as demonstrated by changing admin settings. CVSS 3.0HIGH 8.8
TI-2019-08604 User/Command/ConfirmEmailHandler.php in Flarum before 0.1.0-beta.8 mishandles invalidation of user email tokens. CVSS 3.0HIGH 7.5

See all 11 →

Sources

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