CVE-2026-57399Network attack vector

Stored XSS via insufficient output escaping

Published Jul 13, 2026 · Updated Jul 13, 2026

Stored XSS in Proxy & VPN Blocker 3.5.8 and earlier allows remote attackers to execute scripts through crafted stored input. The upstream changelog identifies output escaping and user-profile display sanitization as corrected areas, but the public advisory does not name the exact input or function. No authentication is required to inject the payload, but execution requires a privileged user to view or act on affected content; impact is limited to that user's browser context.

CVSS severity7.1
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Proxy & VPN Blocker 3.5.8 and earlier allows remote attackers to execute scripts through crafted stored input. The upstream changelog identifies output escaping and user-profile display sanitization as corrected areas, but the public advisory does not name the exact input or function. No authentication is required to inject the payload, but execution requires a privileged user to view or act on affected content; impact is limited to that user's browser context.

The record

CVE
CVE-2026-57399
Published
Jul 13, 2026
Updated
Jul 13, 2026
Vendor
Proxy & VPN Blocker
Product
Proxy & VPN Blocker
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.5.8 changes=[{"at":"3.5.9","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Proxy & VPN Blocker · Proxy & VPN Blockerversion=0 <=3.5.8 changes=[{"at":"3.5.9","status":"unaffected"}]

Published CVSS scores

7.1PatchstackCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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