CVE-2023-4520 | FV Flowplayer Video Player <= 7.5.37.7212 - Insufficient Input Validation to Unauthenticated Stored Cross-Site Scripting and Arbitrary Usermeta Update

The FV Flowplayer Video Player plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘_fv_player_user_video’ parameter saved via the 'save' function hooked via init, and the plugin is also vulnerable to Arbitrary Usermeta Update via the 'save' function in versions up to, and including, 7.5.37.7212 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page, and makes it possible to update the user metas arbitrarily, but the meta value can only be a string.

Published: 2023-08-25 Last update: 2026-04-08 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-4520 is rated Moderate Risk (48.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.97%). Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2023-4520

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 2026-05-20 0.78% 0.97% +0.19%
2 2025-11-21 2.40% 0.78% -1.62%
3 2025-11-18 — 2.40% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-4520

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 2.7 [email protected]
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N 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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2023-4520

Affected software / configurations for CVE-2023-4520

Vendor Product Version Raw CPE
foliovision fv_flowplayer_video_player <= 7.5.37.7212 cpe:2.3:a:foliovision:fv_flowplayer_video_player:*:*:*:*:*:wordpress:*:*

References for CVE-2023-4520

cvelogic Threat Intelligence