Cotonti through 1.0.0 Open Redirect via message.php redirect parameter (CVE-2026-100523) | HOL Guard CVE

Medium · CVSS 5.1CVE-2026-100523

Cotonti through 1.0.0 Open Redirect via message.php redirect parameter

Answer in brief

CVE-2026-100523 records a Medium severity (CVSS 5.1) vulnerability in Cotonti through 1.0.0 Open Redirect via message.php redirect parameter. The current sources do not mark it as known exploited. The current feed maps Cotonti/Cotonti (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 26, 2026Updated Sep 26, 2026Source checked Sep 26, 2026First seen by HOL Sep 26, 2026Material review Sep 26, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 5.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Cotonti/Cotonti (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Cotonti/Cotontigeneric	>=0 <=1.0.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Cotonti/Cotonti.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 26, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 26, 2026

Sources and claim methodology

Upstream source description

Cotonti through 1.0.0 contains an open redirect vulnerability in message.php that base64-decodes the redirect parameter without domain validation. Unauthenticated attackers can craft malicious links with encoded external URLs to redirect users to arbitrary sites via meta refresh tags for phishing attacks.

Quoted source text, attributed separately from HOL analysis.