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Spring SecurityFramework / library · VMware

CVE-2017-4995

HIGH · 8.1 CVSS v3.1 Published 2017-11-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
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
An issue was discovered in Pivotal Spring Security 4.2.0.RELEASE through 4.2.2.RELEASE, and Spring Security 5.0.0.M1. When configured to enable default typing, Jackson contained a deserialization vulnerability that could lead to arbitrary code execution. Jackson fixed this vulnerability by blacklisting known "deserialization gadgets." Spring Security configures Jackson with global default typing enabled, which means that (through the previous exploit) arbitrary code could be executed if all of the following is true: (1) Spring Security's Jackson support is being leveraged by invoking SecurityJackson2Modules.getModules(ClassLoader) or SecurityJackson2Modules.enableDefaultTyping(ObjectMapper); (2) Jackson is used to deserialize data that is not trusted (Spring Security does not perform deserialization using Jackson, so this is an explicit choice of the user); and (3) there is an unknown (Jackson is not blacklisting it already) "deserialization gadget" that allows code execution present on the classpath. Jackson provides a blacklisting approach to protecting against this type of attack, but Spring Security should be proactive against blocking unknown "deserialization gadgets" when Spring Security enables default typing.

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

Spring Security 4.2.0-4.2.2 and 5.0.0.M1 configure Jackson with global default typing enabled when using SecurityJackson2Modules.getModules() or enableDefaultTyping(). When Jackson deserializes untrusted data with default typing enabled, attackers can exploit deserialization gadgets to achieve arbitrary code execution. Jackson's blacklist approach is insufficient because unknown gadgets not yet blacklisted can still be leveraged.

MitigationDisable default typing in Jackson configuration and use explicit type handling instead; ensure untrusted data is never deserialized using Jackson; remove or replace any known deserialization gadgets from the classpath; upgrade to a patched Spring Security version.

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
Spring SecurityFramework / library
Affected:= 4.2.0= 4.2.1= 4.2.2= 5.0.0

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
High
Availability
High

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

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 your Spring Security version
    Check the Spring Security JAR file name or dependency management (Maven pom.xml, Gradle build.gradle) for the exact version number
    Affected if The version is 4.2.0, 4.2.1, 4.2.2, or 5.0.0 (including 5.0.0.M1)
  2. Locate Jackson module registration code
    Search your codebase for calls to SecurityJackson2Modules.getModules() or enableDefaultTyping() methods - these are typically in a Jackson ObjectMapper configuration class
    Affected if Either of these methods are called, which enables default typing in Jackson
  3. Inspect Jackson ObjectMapper configuration
    Review your ObjectMapper bean definition or configuration to check if default typing is explicitly enabled - look for enableDefaultTyping() or DEFAULT_TYPING settings
    Affected if Default typing is enabled on the ObjectMapper used with Spring Security
  4. Identify deserialization entry points
    Search for code that deserializes JSON using ObjectMapper (readValue, readTree, or similar methods) - particularly any that process external or untrusted input
    Affected if Your application deserializes JSON data from external sources using Jackson with the affected Spring Security configuration

You are affected if your Spring Security version is 4.2.0-4.2.2 or 5.0.0.M1 AND you use SecurityJackson2Modules.getModules() or enableDefaultTyping() with Jackson deserialization of untrusted data

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Disable default typing in Jackson configuration and use explicit type handling instead; ensure untrusted data is never deserialized using Jackson; remove or replace any known deserialization gadgets from the classpath; upgrade to a patched Spring Security version.

Fix this in Spring Security Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,640
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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-2017-4995 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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