CVE-2025-66305 | Grav vulnerable to Denial of Service via Improper Input Handling in 'Supported' Parameter

Exp

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, a Denial of Service (DoS) vulnerability was identified in the "Languages" submenu of the Grav admin configuration panel (/admin/config/system). Specifically, the Supported parameter fails to properly validate user input. If a malformed value is inserted—such as a single forward slash (/) or an XSS test string—it causes a fatal regular expression parsing error on the server. This leads to application-wide failure due to the use of the preg_match() function with an improperly constructed regular expression, resulting in an error. Once triggered, the site becomes completely unavailable to all users. This vulnerability is fixed in 1.8.0-beta.27.

Published: 2025-12-01 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-66305 is rated Exploit Available (51.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.33%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2025-66305

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-66305

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.06% 0.33% +0.27%
2 2026-04-29 0.22% 0.06% -0.16%
3 2026-04-02 — 0.22% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-66305

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.9 4.0 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:H)
High privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:N)
No confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
4.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.2 3.6 [email protected]

Weakness enumeration for CVE-2025-66305

GitHub Security Advisory for CVE-2025-66305

GHSA-m8vh-v6r6-w7p6 · Severity: high · Ecosystem: composer — Grav vulnerable to Denial of Service via Improper Input Handling in 'Supported' Parameter

Affected software / configurations for CVE-2025-66305

Vendor Product Version Raw CPE
getgrav grav >= 1.7.48, < 1.8.0 cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta1:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta10:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta11:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta12:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta13:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta14:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta15:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta16:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta17:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta18:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta19:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta2:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta20:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta21:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta22:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta23:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta24:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta25:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta26:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta3:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta4:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta5:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta6:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta7:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta8:*:*:*:*:*:*
getgrav grav 1.8.0 cpe:2.3:a:getgrav:grav:1.8.0:beta9:*:*:*:*:*:*

References for CVE-2025-66305

cvelogic Threat Intelligence