Remote code execution via attacker-controlled object reconstruction
Published Mar 22, 2021 · Updated Aug 3, 2024
Unsafe deserialization in XStream before 1.4.16 allows remote attackers to execute arbitrary code through a manipulated input stream. XStream's unmarshalling path trusts embedded type metadata and instantiates attacker-selected gadget objects without a restrictive allowlist. Exposure requires an application to unmarshal attacker-controlled data with the default blacklist; the gadget chain loads and executes code from a remote server.
Summary
What happened
Unsafe deserialization in XStream before 1.4.16 allows remote attackers to execute arbitrary code through a manipulated input stream. XStream's unmarshalling path trusts embedded type metadata and instantiates attacker-selected gadget objects without a restrictive allowlist. Exposure requires an application to unmarshal attacker-controlled data with the default blacklist; the gadget chain loads and executes code from a remote server.
The record
- CVE
- CVE-2021-21347
- Published
- Mar 22, 2021
- Updated
- Aug 3, 2024
- Vendor
- XStream
- Product
- XStream
- Classifications
- CWE-502, CWE-434
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 22, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.4.16
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream crafted PriorityQueue XML reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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