dbcve.org
TomcatWeb server / proxy · Apache

CVE-2021-24122

MEDIUM · 5.9 CVSS v3.1 Published 2021-01-14
Fix available
A fix is available. Upgrade to after 9.0.39 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
When serving resources from a network location using the NTFS file system, Apache Tomcat versions 10.0.0-M1 to 10.0.0-M9, 9.0.0.M1 to 9.0.39, 8.5.0 to 8.5.59 and 7.0.0 to 7.0.106 were susceptible to JSP source code disclosure in some configurations. The root cause was the unexpected behaviour of the JRE API File.getCanonicalPath() which in turn was caused by the inconsistent behaviour of the Windows API (FindFirstFileW) in some circumstances.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache Tomcat versions prior to 10.0.0-M10, 9.0.40, 8.5.60, and 7.0.107 have a JSP source code disclosure vulnerability when serving resources from Windows network shares using NTFS file system. The issue stems from inconsistent behavior of the Windows API FindFirstFileW which causes File.getCanonicalPath() to return unexpected paths, allowing attackers to bypass JSP execution and retrieve source code instead.

MitigationUpgrade Apache Tomcat to version 10.0.0-M10 or later (10.0.x), 9.0.40 or later (9.0.x), 8.5.60 or later (8.5.x), or 7.0.107 or later (7.0.x). If upgrading is not feasible, avoid serving resources from network locations on Windows NTFS file systems.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
TomcatWeb server / proxy
Affected:>= 7.0.0, <= 7.0.106>= 8.5.0, <= 8.5.59>= 9.0.1, <= 9.0.39= 9.0.0= 10.0.0
Debian LinuxOperating system
Affected:= 9.0
Agile PlmApplication
Affected:= 9.3.3= 9.3.6

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Apache Tomcat version
    Run 'catalina.sh version' or check the version.jar file in the Tomcat lib directory, or look at the RELEASE-NOTES file in the Tomcat home directory
    Affected if The installed version falls within 7.0.0 to 7.0.106, 8.5.0 to 8.5.59, 9.0.0 to 9.0.39, or equals 10.0.0-M10 or 10.0.0 (note: 10.0.0-M10 is actually fixed, so only 10.0.0 is affected)
  2. Determine if Tomcat serves content from network shares
    Review the server.xml configuration file and any web application context configurations to identify if the docBase, alias, or any resource paths are specified as UNC paths (\\server\share)
    Affected if The docBase or any resource path points to a Windows network share (UNC path beginning with \\\\)
  3. Verify the operating system and file system
    Check the OS type by running 'uname -a' on Linux or 'systeminfo' on Windows, and determine if the served network share uses NTFS by examining the remote share properties or mounting configuration
    Affected if Tomcat is running on Windows and serving content from a network share that uses NTFS file system
  4. Check for JSP file access patterns
    Review web server access logs for requests to .jsp files that return source code (HTTP 200 with Content-Type not being application/octet-stream or the JSP source visible in response) rather than executing the JSP
    Affected if JSP files are being served as plain text instead of being executed, exposing source code

You are affected if you run a vulnerable Apache Tomcat version (7.0.0-7.0.106, 8.5.0-8.5.59, 9.0.0-9.0.39, or 10.0.0) on Windows while serving web application content from an NTFS network share, allowing attackers to retrieve JSP source code instead of executed output.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 9.0.39
Interim mitigation

Upgrade Apache Tomcat to version 10.0.0-M10 or later (10.0.x), 9.0.40 or later (9.0.x), 8.5.60 or later (8.5.x), or 7.0.107 or later (7.0.x). If upgrading is not feasible, avoid serving resources from network locations on Windows NTFS file systems.

Fix this in Tomcat Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-24122 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data