CVE & CISA-KEV Catalog

CVE-2026-100523

MEDIUM
6.1
CVSS v3
NVD

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.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged

Impact

ConfidentialityLow
IntegrityLow
AvailabilityNone

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

Exploit Intelligence

0.19%probability of exploitation in 30 days
8thpercentile

Low risk: more likely to be exploited than 8% of all known CVEs.

References

Related Vulnerabilities

Other CWE-601 (Open Redirect) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2018-11784Medium4.398%-Fix
CVE-2025-4123High7.697%-Fix
CVE-2021-22881Medium6.187%-Fix
CVE-2022-45402Medium6.182%-Fix
CVE-2017-1000117High8.878%-Fix
CVE-2025-6197Medium4.274%--

Common questions

How do I fix CVE-2026-100523?

No published fix for CVE-2026-100523 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

Is CVE-2026-100523 being actively exploited?

Not that we know of. CVE-2026-100523 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.19% is the estimated probability that it will be exploited in the next 30 days. That is higher than 8% of all scored CVEs.

How severe is CVE-2026-100523?

CVE-2026-100523 has a CVSS v3 base score of 6.1, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-05.