Medium

Azure Monitor Log Analytics XSS Spoofing Vulnerability

IdentifiersCVE-2025-55321CWE-79· Improper Neutralization of Input…

CVE-2025-55321 is a high-severity cross-site scripting vulnerability in Azure Monitor Log Analytics. According to the provided content, the flaw is caused by improper neutralization of attacker-controlled input during web page generation, resulting in unsafe rendering within the Azure Monitor web interface. This allows an authorized attacker to inject malicious content that is rendered in the Log Analytics portal and used to spoof information presented to users. Publicly provided details do not identify the exact vulnerable parameter, function, or request path, and no affected version list is given; the record indicates an exclusively hosted service rather than versioned on-prem software.

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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 enables spoofing within the Azure Monitor Log Analytics portal, with the potential to manipulate or falsify information displayed in dashboards, alerts, or other monitoring views. Based on the provided CVSS vector and supporting context, the primary impacts are high confidentiality and integrity impact, with no stated availability impact. In practice, this could mislead defenders, disrupt incident triage and response, and expose sensitive monitoring data or trusted portal content to attacker-controlled manipulation.

Mitigation

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

Until full remediation details are confirmed, limit exposure by restricting access to Azure Monitor Log Analytics to only necessary privileged users, reviewing and minimizing high-privilege roles, and monitoring for anomalous or unexpected content rendered in dashboards, alerts, and portal views. Treat suspicious portal output as potentially untrusted, and use compensating controls such as conditional access, strong session protection, and logging review for privileged Azure Monitor activity. The provided content does not include a specific vendor-recommended mitigation beyond Microsoft's advisory.

Remediation

Patch, then assume compromise.

Apply Microsoft's service-side remediation for CVE-2025-55321 as made available through Azure Monitor / Azure Monitor Log Analytics. Because the provided content identifies this as an exclusively hosted service and does not list affected versions or customer-applied patches, remediation is dependent on Microsoft's backend fix. Organizations should review the MSRC advisory for CVE-2025-55321 and confirm whether any tenant-side actions, portal updates, or configuration changes are required once Microsoft publishes them.

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

Microsoft CorporationAzure Monitorapplication

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

talos intelligence blogNews

Oct 14, 2025

Microsoft Patch Tuesday for October 2025 — Snort rules and prominent vulnerabilities

A cross-site scripting (XSS) vulnerability in Azure Monitor Log Analytics portal, allowing network attackers to perform spoofing attacks.

cvefeed high severityNews

Oct 9, 2025

CVE-2025-55321 - Azure Monitor Log Analytics Spoofing Vulnerability

A high-severity cross-site scripting (XSS) vulnerability in Azure Monitor Log Analytics that allows an authorized attacker to perform spoofing attacks over a network. The flaw is due to improper input neutralization during web page generation.

zeropath blogNews

Oct 9, 2025

Azure Monitor CVE-2025-55321 XSS Vulnerability: Brief Summary and Technical Review - ZeroPath Blog | ZeroPath

A high-severity cross-site scripting vulnerability in Azure Monitor that could allow an authorized attacker with network access to inject malicious input into the web interface and spoof content in the Azure Monitor portal.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

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

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

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

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2025-55321

NVD

nvd.nist.gov/vuln/detail/CVE-2025-55321

MITRE CWE · CWE-79

Improper Neutralization of Input During Web…

Vendor Advisory

msrc.microsoft.com/update-guide/vulnerability/CVE-2025-55321