Out-of-bounds read via unchecked aligned varint bounds
Published Jul 21, 2026 · Updated Jul 21, 2026
Out-of-bounds read in Apache Fory allows remote attackers to read beyond a Java buffer via crafted zero-copy serialized data. The readAlignedVarUint() path uses sun.misc.Unsafe without enforcing the underlying buffer boundary while decoding an aligned variable-length integer. The vulnerable path is reachable only when an application enables the opt-in out-of-band zero-copy deserialization feature; other configurations are unaffected.
Summary
What happened
Out-of-bounds read in Apache Fory allows remote attackers to read beyond a Java buffer via crafted zero-copy serialized data. The readAlignedVarUint() path uses sun.misc.Unsafe without enforcing the underlying buffer boundary while decoding an aligned variable-length integer. The vulnerable path is reachable only when an application enables the opt-in out-of-band zero-copy deserialization feature; other configurations are unaffected.
The record
- CVE
- CVE-2026-64609
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- The Apache Software Foundation
- Product
- Apache Fory
- Classifications
- CWE-125
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0.11.0 <1.4.0
- Affected versionversion=0.5.0 <0.11.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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