Unrated

XSS in Apache Tomcat number guess example

IdentifiersCVE-2026-50229CWE-80

CVE-2026-50229 is a basic cross-site scripting vulnerability in the Apache Tomcat number guess example application. Apache describes the issue as improper neutralization of script-related HTML tags in a web page. The flaw affects the example application shipped with multiple Tomcat branches rather than the core servlet container itself, based on the provided description. Affected versions are Apache Tomcat 11.0.0-M1 through 11.0.22, 10.1.0-M1 through 10.1.55, 9.0.0.M1 through 9.0.118, 8.5.0 through 8.5.100, and 7.0.0 through 7.0.109; unsupported end-of-life versions may also be affected.

For your environment

Are you exposed to this one?

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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 an attacker to inject and execute malicious script in a victim's browser in the context of the vulnerable number guess example page. This can enable client-side actions such as session theft, page content manipulation, phishing-style UI injection, or other browser-based attacks against users who access the crafted page or input. The provided material characterizes the issue as low severity.

Mitigation

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

If immediate upgrade is not possible, remove or disable the vulnerable number guess example application from Tomcat deployments, especially on internet-accessible systems. More broadly, do not deploy sample/example web applications in production. Restrict access to example applications and minimize exposure until patched versions are installed. Specific temporary code-level mitigations are not provided in the supplied content.

Remediation

Patch, then assume compromise.

Upgrade Apache Tomcat to a fixed release. Apache recommends upgrading to 11.0.23, 10.1.56, or 9.0.119, which contain the fix. For deployments still using affected 8.5.x or 7.0.x branches, move to a supported fixed branch because the provided advisory does not list fixed releases for those end-of-support lines. Other unsupported versions may also be affected and should likewise be retired or upgraded.

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

Apache Software FoundationTomcatapplication

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

ACTIVITY FEED

Recent activity

8 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

8 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

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 activity8

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

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-50229

NVD

nvd.nist.gov/vuln/detail/CVE-2026-50229

MITRE CWE · CWE-80

cwe.mitre.org