Grav before 2.0.15 Arbitrary File Write via error_log

published 2026-08-18 2 mo ago modified 2026-10-22 17 d ago also GHSA-f8wv-xp27-6gq7 , EUVD-2026-60591

cvss: 8.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits: 0; none known

Grav before 2.0.15 contains an arbitrary file write vulnerability in the Blueprint dynamic-data bare-function validation that uses an incomplete denylist instead of a positive allowlist. Attackers with page-edit or blueprint-config access can invoke the error_log function through a data directive to append PHP payloads to web-accessible files, achieving remote code execution.

Patch / fix

fixed in 2

packagist getgrav/grav 2.0.15
getgrav grav 2.0.15

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 2 mo ago (2026-08-19)

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/getgrav/grav/security/advisories/GHSA-f8wv-xp27-6gq7 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA	4.0	9.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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
GitHub	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
packagist	getgrav/grav	<2.0.15	2.0.15

Affected products

getgrav grav

Classification

Weakness

CWE-94 Improper Control of Generation of Code

References

github.com /getgrav/grav/security/advisories/GHSA-f8wv-xp27-6gq7
vendor-advisory, exploit, web
vulncheck.com /advisories/grav-before-arbitrary-file-write-via-error-log
third-party-advisory, web
nvd.nist.gov /vuln/detail/CVE-2026-75827
advisory
github.com /getgrav/grav
package

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.

Summary