CVE-2026-34451

Claude SDK for TypeScript: Memory Tool Path Validation Allows Sandbox Escape to Sibling Directories

MEDIUM
5.4
CVSS Score
Published: March 31, 2026 at 09:35 PM UTC
Updated: July 24, 2026 at 09:20 PM UTC
2 products affected across 2 vendorsClaude SDK for TypeScriptClaude SDK for TypeScript

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

Claude SDK for TypeScript provides access to the Claude API from server-side TypeScript or JavaScript applications. From version 0.79.0 to before version 0.81.0, the local filesystem memory tool in the Anthropic TypeScript SDK validated model-supplied paths using a string prefix check that did not append a trailing path separator. A model steered by prompt injection could supply a crafted path that resolved to a sibling directory sharing the memory root's name as a prefix, allowing reads and writes outside the sandboxed memory directory. This issue has been patched in version 0.81.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.79.0 ≤ v < 0.81.0
Affected range stops below 0.81.0, so it looks safe — our inference, not a vendor statement
v < 0.81.0
Affected range stops below 0.81.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22CWE-41

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