CVE-2026-7839Network attack vector

Unauthenticated admin access via hardcoded default password

Published Jul 1, 2026 · Updated Jul 1, 2026

Hardcoded credentials in UltraVNC Repeater 1.8.2.2 and earlier allow remote attackers to gain administrative access over HTTP. When settings2.txt is absent, repeater/webgui/settings.c copies the literal default into saved_password, and wi_decode_auth() accepts it without rate limiting or lockout. Reachability of the HTTP administration port is the only network gate; a fresh or unmodified installation exposes configuration rules and session visibility.

CVSS severity9.1
Critical
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hardcoded credentials in UltraVNC Repeater 1.8.2.2 and earlier allow remote attackers to gain administrative access over HTTP. When settings2.txt is absent, repeater/webgui/settings.c copies the literal default into saved_password, and wi_decode_auth() accepts it without rate limiting or lockout. Reachability of the HTTP administration port is the only network gate; a fresh or unmodified installation exposes configuration rules and session visibility.

The record

CVE
CVE-2026-7839
Published
Jul 1, 2026
Updated
Jul 1, 2026
Vendor
UltraVNC Team
Product
UltraVNC
Classifications
CWE-798, T1078.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 1, 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 <=1.8.2.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

UltraVNC Team · UltraVNCversion=0 <=1.8.2.2

Published CVSS scores

9.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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-798Use of Hard-coded Credentials
T1078.001Valid Accounts: Default Accounts

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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