Grav: Low-privileged API users can create super-admin accounts via blueprint-upload

published 2026-05-06 6 mo ago modified 2026-10-26 13 d ago also GHSA-6xx2-m8wv-756h , EUVD-2026-29857

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 27%
public exploits: 0; none known

Grav is a file-based Web platform. In Grav 2.0.0-beta.2, a low-privileged authenticated API user with api.media.write can abuse /api/v1/blueprint-upload to write an arbitrary YAML file into user/accounts/, then log in as the newly created account with api.super privileges. This results in full administrative compromise of the Grav API. This vulnerability is fixed in API 1.0.0-beta.17.

Patch / fix

fixed in 1 links 1

packagist getgrav/grav 2.0.0-beta.4

github.com/getgrav/grav-plugin-api@97fc028 commit

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 5 mo ago (2026-05-13)

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/getgrav/grav/security/advisories/GHSA-6xx2-m8wv-756h referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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
NVD	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	<2.0.0-beta.4	2.0.0-beta.4

Affected products

getgrav grav

Classification

Weakness

CWE-434 Unrestricted Upload of File with Dangerous Type
CWE-269 Improper Privilege Management

References

github.com /getgrav/grav-plugin-api/commit/97fc02844a35f743dfe93d34efd92d47eedd5bc5
web
github.com /getgrav/grav/security/advisories/GHSA-6xx2-m8wv-756h
exploit, web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-42844
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