Local agent-state disclosure and modification via permissive modes
Published Mar 31, 2026 · Updated Mar 31, 2026
Incorrect file permissions in Anthropic Python SDK 0.86.0 allow local users to read or modify persisted agent state. The synchronous and asynchronous local filesystem memory tools pass mode 0o666 to os.open when creating memory files, allowing the process umask to leave them accessible to other users. Exploitation requires local access to a shared host or container filesystem; standard umasks expose reads, while permissive umasks also permit state changes that influence later model behavior.
Summary
What happened
Incorrect file permissions in Anthropic Python SDK 0.86.0 allow local users to read or modify persisted agent state. The synchronous and asynchronous local filesystem memory tools pass mode 0o666 to os.open when creating memory files, allowing the process umask to leave them accessible to other users. Exploitation requires local access to a shared host or container filesystem; standard umasks expose reads, while permissive umasks also permit state changes that influence later model behavior.
The record
- CVE
- CVE-2026-34450
- Published
- Mar 31, 2026
- Updated
- Mar 31, 2026
- Vendor
- Anthropic
- Product
- Anthropic Python SDK
- Classifications
- CWE-276, CWE-732, T1565.001, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 31, 2026CVE publishedPublication date reported by the CVE source.
- Mar 31, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 0.86.0, < 0.87.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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