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Mallory
High

Cisco IOS Web UI Denial of Service via Crafted URL

IdentifiersCVE-2025-20327CWE-20

CVE-2025-20327 is a denial-of-service vulnerability in the web UI of Cisco IOS Software affecting Cisco IOS industrial switch platforms. According to the provided content, the flaw is caused by improper input validation in the web interface. An authenticated remote attacker with low privileges can exploit the issue by sending a crafted URL in an HTTP request to the affected device. Successful exploitation causes the device to reload, resulting in a denial-of-service condition.

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ANALYST BRIEF

Impact, mitigation & remediation

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Impact

What an attacker gets, and what they’ve been doing with it.

A successful exploit can force the affected Cisco IOS device to reload, interrupting normal operation and causing a denial-of-service condition. This can disrupt management access and network services provided by the impacted industrial switch until the device finishes reloading and returns to service.

Mitigation

If you can’t patch tonight, do this now.

The provided content does not describe specific mitigations other than following Cisco's guidance and updating affected products. Where immediate patching is not possible, limiting exposure of the web UI, restricting HTTP/HTTPS management access to trusted administrative networks, and minimizing low-privilege account access may reduce exploitability, but vendor-specific mitigation information is not available in the provided content.

Remediation

Patch, then assume compromise.

Cisco recommends updating affected products in accordance with its published vulnerability advisory and device/version-specific guidance. Apply the fixed Cisco IOS software release identified by Cisco for the affected industrial switch models.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

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Social activity3

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