CVE-2023-27577

CVE-2023-27577 is a medium-severity vulnerability in Flarum with a CVSS 3.x base score of 6.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Description

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.

Frequently asked questions

What is CVE-2023-27577?
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.
How severe is CVE-2023-27577?
CVE-2023-27577 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2023-27577 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-27577?
CVE-2023-27577 affects Flarum. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-27577?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-27577 published?
CVE-2023-27577 was published on 2023-03-10 and last updated on 2026-06-17.

References

Affected products (1)

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