CVE-2026-61873

HIGHCVSS 8.1/10

Last modified

CVE-2026-61873 is a high-severity vulnerability rated 8.1/10 on the CVSS scale. Grav before 9.1.8 contains an arbitrary file write vulnerability in the Form plugin's process.save.filename parameter, which is validated against path traversal before Twig processing but never re-validated after rendering. Attackers can submit form data containing path traversal sequences that are processed through Twig templates, allowing them to write arbitrary files including PHP webshells to the web root or other sensitive directories..

Description

Grav before 9.1.8 contains an arbitrary file write vulnerability in the Form plugin's process.save.filename parameter, which is validated against path traversal before Twig processing but never re-validated after rendering. Attackers can submit form data containing path traversal sequences that are processed through Twig templates, allowing them to write arbitrary files including PHP webshells to the web root or other sensitive directories.

Metrics

CVSS 3.1
8.1/10

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

CVSS 4.0
7.2/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
getgravgrav< 9.1.8

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-61873?
Grav before 9.1.8 contains an arbitrary file write vulnerability in the Form plugin's process.save.filename parameter, which is validated against path traversal before Twig processing but never re-validated after rendering. Attackers can submit form data containing path traversal sequences that are processed through Twig templates, allowing them to write arbitrary files including PHP webshells to the web root or other sensitive directories.
How severe is CVE-2026-61873?
CVE-2026-61873 has a CVSS score of 8.1/10 (HIGH severity).
How do I fix CVE-2026-61873?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST