CyberSecBulletin
CVE-2025-20327NVD status: Analyzed

IOS: Improper Validation of Specified Type of Input

Published Updated By the CyberSecBulletin desk

CVE-2025-20327 is a high-severity improper validation of specified type of input vulnerability in IOS from Cisco, with a CVSS 3.1 base score of 7.7 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected IOS versions: 15.2(6)E2; 15.2(7)E; 15.2(6)E2a, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of IOS you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
CiscoIOS15.2(6)E2; 15.2(7)E; 15.2(6)E2a; 15.2(6)E2b; 15.2(7)E1; 15.2(7)E0a; 15.2(7)E0b; 15.2(7)E0s; and 21 more rangesNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H. Scored by CNA (cisco.com).

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Validation of Specified Type of Input

The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type.

More Improper Validation of Specified Type of Input vulnerabilities (CWE-1287)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in IOS

All IOS vulnerabilities

Recent Improper Validation of Specified Type of Input vulnerabilities

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