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CVE-2026-42608

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

Published: May 11, 2026Updated: May 13, 2026 Sources: CVE List NVDCWE-22
NVD MITRE
9.1CVSSCRITICAL
EPSS Score
0.5%
Top 60.0%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-22

Affected Products

gravgetgrav
On-prem
Web & CMS Plugins / cms-core
getgravoss-projectWeb & CMS Pluginsaka grav, grav-plugin-admin, getgrav/grav

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Collection
Discovery
View detailed technique mapping

References

https://github.com/getgrav/grav/security/advisories/GHSA-hmcx-ch82-3fv2
github.com

Timeline

Published
May 11, 2026
Last Updated
May 13, 2026

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