---
title: "CVE-2026-75827: Grav: Blueprint dynamic-data bare-function branch is denylist-gated and omits error_log, giving arbitrary file write"
url: https://erroneo.us/security/cve/CVE-2026-75827/
description: "CVE-2026-75827 (getgrav/grav (Composer (PHP))): Grav before 2.0.15 contains an arbitrary file write vulnerability in the Blueprint dynamic-data…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-18
date_modified: 2026-10-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-75827"
kev: false
cvss: 9.3
epss: 0.00859
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-75827: Grav: Blueprint dynamic-data bare-function branch is denylist-gated and omits error_log, giving arbitrary file write

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.9% , percentile 58: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 58% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes getgrav/grav (Composer (PHP)) <= 2.0.14, fixed in 2.0.15 . Check your lockfile, including transitive dependencies.

## What it is

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 errorlog function through a data directive to append PHP payloads to web-accessible files, achieving remote code execution.

## Affected packages

- Composer (PHP) `getgrav/grav` <= 2.0.14 → fixed: 2.0.15

## Affected products (CVE record)

- getgrav grav: < 2.0.15

## Severity

- VulnCheck CVSS 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`
- VulnCheck CVSS 3.1: 8.8 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 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`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.86% probability of exploitation activity in the next 30 days; percentile 58.

## Sources

- [GitHub Security Advisory (GHSA-f8wv-xp27-6gq7)](https://github.com/getgrav/grav/security/advisories/GHSA-f8wv-xp27-6gq7)
- [GitHub Advisory GHSA-f8wv-xp27-6gq7](https://github.com/advisories/GHSA-f8wv-xp27-6gq7)
- [CVE.org record CVE-2026-75827](https://www.cve.org/CVERecord?id=CVE-2026-75827)
- [NVD entry CVE-2026-75827](https://nvd.nist.gov/vuln/detail/CVE-2026-75827)
- [VulnCheck Advisory: Grav before 2.0.15 Arbitrary File Write via error_log](https://www.vulncheck.com/advisories/grav-before-arbitrary-file-write-via-error-log)

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Source page: https://erroneo.us/security/cve/CVE-2026-75827/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt