RCE in Getgrav Grav

CVE-2023-34253

Grav is a flat-file content management system. Prior to version 1.7.42, the denylist introduced in commit 9d6a2d to prevent dangerous functions from being executed via injection of malicious templates was insufficient and could be easily subverted in multiple ways -- (1) using unsafe functions that are not banned, (2) using capitalised callable names, and (3) using fully-qualified names for referencing callables. Consequently, a low privileged attacker with login access to Grav Admin panel and page creation/update permissions is able to inject malicious templates to obtain remote code execution. A patch in version 1.7.42 improves the denylist.

EPSS: 0.021 (79.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-34253?
CVE-2023-34253 is a high-severity vulnerability in Getgrav Grav, classified under Incomplete List of Disallowed Inputs. CVSS score: 8.8/10. Published 2023-06-14.
How severe is CVE-2023-34253?
High severity. CVSS v3 base score is 8.8 out of 10.