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Fencer Vulns
high 8.1

CVE-2026-61873 json

Grav before 9.1.8 Arbitrary File Write via Twig-Processed Filename

published 2026-07-15 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-44621

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

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.

Patch / fix

  • getgrav grav 9.1.8

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/getgrav/grav/security/advisories/GHSA-q532-mvx7-42qg referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.2 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
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
CNA 4.0 7.2 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

Affected products

  • getgrav grav

Classification

Weakness
  • CWE-73 External Control of File Name or Path

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.