CVE-2026-78087Network attack vector

Stored XSS via unescaped Group Block attributes

Published Oct 15, 2026 · Updated Oct 15, 2026

Stored XSS in VK Blocks 1.126.1 and earlier allows remote authenticated users to execute scripts via Group Block links. The linkToPost feature outputs attacker-controlled HTML attributes without sufficient sanitization or escaping. Contributor-level access or above permits injection into stored content; scripts execute in a visitor's browser when the affected page is accessed.

CVSS severity6.4
Medium
EPSS probability0.19%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in VK Blocks 1.126.1 and earlier allows remote authenticated users to execute scripts via Group Block links. The linkToPost feature outputs attacker-controlled HTML attributes without sufficient sanitization or escaping. Contributor-level access or above permits injection into stored content; scripts execute in a visitor's browser when the affected page is accessed.

The record

CVE
CVE-2026-78087
Published
Oct 15, 2026
Updated
Oct 15, 2026
Vendor
Vektor,Inc.
Product
VK Blocks
Classifications
CWE-79
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 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 <=1.126.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Vektor,Inc. · VK Blocksversion=0 <=1.126.1

Published CVSS scores

6.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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