Medium

Reflected XSS in Cisco IOS XE Web Authentication

IdentifiersCVE-2025-20240CWE-79

CVE-2025-20240 is a reflected cross-site scripting vulnerability in the Web Authentication feature of Cisco IOS XE Software. According to the provided content, the flaw is caused by improper sanitization of user-supplied input in the device management/web authentication interface. An unauthenticated remote attacker can exploit the issue by crafting a malicious link and persuading a user to follow it. If triggered in a victim’s browser, the injected script is reflected by the affected device and executed in the security context of the Cisco IOS XE web interface.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

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

Successful exploitation allows execution of attacker-controlled script in the victim user’s browser in the context of the affected Cisco IOS XE device interface. The provided content specifically states that this can enable theft of user cookies from the affected device. Depending on the victim’s authenticated session and browser context, this may permit session hijacking and unauthorized access to the management interface with the victim’s privileges.

Mitigation

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

If immediate patching is not possible, reduce exposure of the Cisco IOS XE web authentication/management interface to untrusted users and networks, and require administrators to access the interface only through trusted channels. Because exploitation requires a victim to click a malicious link, user awareness and limiting access to the web interface can reduce risk. However, the provided content does not describe a vendor-supplied workaround, so patching should be treated as the primary corrective action.

Remediation

Patch, then assume compromise.

Apply the Cisco software updates that address CVE-2025-20240, following Cisco’s product-specific advisory and version guidance for affected IOS XE devices. The provided content indicates that Cisco included a patch for this vulnerability in the relevant IOS XE security update bundle.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Cisco SystemsIos Xeoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

6 SOURCESView more in app

kyberturvallisuuskeskus alertsNews

Sep 26, 2025

Haavoittuvuuksia Cisco IOS ja IOS XE -laitteissa | Traficom

A cross-site scripting vulnerability in the Cisco IOS XE management interface.

kyberturvallisuuskeskus alertsNews

Sep 26, 2025

Haavoittuvuuksia Cisco IOS ja IOS XE -laitteissa | Traficom

A cross-site scripting vulnerability in the Cisco IOS XE management interface.

cyberscoopNews

Sep 25, 2025

Cisco uncovers new SNMP vulnerability used in attacks on IOS devices

A reflected cross-site scripting (XSS) vulnerability in Cisco IOS/IOS XE that could allow attackers to steal session cookies.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3