CVE-2026-115391

Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 Unbounded Heap Allocation via WASIp3 Streams

MEDIUM
5.8
CVSS Score
Published: October 22, 2026 at 07:13 PM UTC
Updated: October 22, 2026 at 07:17 PM UTC
1 product affected across 1 vendorWasmtime

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Severity
MEDIUM5.8
Exploit prediction
EPSS 0.2%

Description

Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 contains an uncontrolled resource allocation vulnerability in its WASIp3 implementation that buffers guest-specified-length writes on the host without limit. Malicious guests can offer large buffers to WASIp3 file or HTTP write streams, causing the host to copy and buffer all bytes, bounded only by guest linear memory, exhausting host memory.

Affected

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

Vendor states this is fixed in 46.0.3 (unaffected)
Vendor states this is fixed in 47.0.4 (unaffected)

Remediation

No guide yet

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

CVSS

5.8MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-770

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