Paper/Archive/CVE-2026-42608

CVE-2026-42608

getgrav grav — Grav: Unauthenticated Path Traversal & Arbitrary File Write in FormFlash component.

CVSS 9.1 (NVD)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 48.8.488 × 209.8 Exploit: SSVC poc+1010.0 SSVC exploitation: poc+100.0

Description · from the CVE record

Grav is a file-based Web platform. Prior to 2.0.0-beta.2, there is a Path Traversal vulnerability within the FormFlash core component. By manipulating the session_id (passed as __form-flash-id in POST requests), an unauthenticated attacker can traverse the filesystem to create arbitrary directories and write an index.yaml file containing attacker-controlled data. This vulnerability can lead to unauthorized modification of application behavior, potential data integrity issues, and service disruption in production environments. This vulnerability is fixed in 2.0.0-beta.2.

Affected

ProductAffectedFixed inSource

grav< 2.0.0-beta.2–CNA

Scores by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

GitHub_M (CNA)8.8CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitgithub.com/getgrav/grav/security/advisories/GHSA-hmcx-ch82-3fv2