CVE-2025-20327: A vulnerability in the web UI of Cisco IOS Software could allow an authenticated, remote attacker with low pri

Routine

HIGH 7.7MITIGATE

CVE-2025-20327 is a high-severity flaw (CVSS 7.7) affecting ios. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability in the web UI of Cisco IOS Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper input validation. An attacker could exploit this vulnerability by sending a crafted URL in an HTTP request. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.7 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-1287
Published	2025-09-24
Last modified	2026-09-26

Publisher (CNA): Cisco Systems, Inc. · Vendor: cisco

Last updated 2026-09-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-09-24 18:15 UTCPublished CVE record published
2026-09-26 00:10 UTCUpdated Record last modified

cisco ios MITIGATE

Affected: 15.2\(6\)e2 · 15.2\(6\)e2a · 15.2\(6\)e2b · 15.2\(6\)e3 · 15.2\(7\)e · 15.2\(7\)e0a · 15.2\(7\)e0b · 15.2\(7\)e0s

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-20327?

ios: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-20327 being exploited?

CVE-2025-20327 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-20327 affect?

CVE-2025-20327 affects ios. Severity is high (CVSS 7.7). A vulnerability in the web UI of Cisco IOS Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper input validat

How urgent is CVE-2025-20327?

Priority 35/100. High severity

Software pages

iOS vulnerabilities · Cisco vulnerabilities

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CVE-2025-20149 MEDIUM 6.5 MITIGATE MITIGATE A vulnerability in the CLI of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, local
CVE-2008-4128 HIGH 8.1 EXPLOITED MITIGATE Cisco IOS Cross-Site Request Forgery Vulnerability

References

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