Medium 5.8Published Oct 22, 2026

CVE-2026-115391Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 Unbounded Heap Allocation via WASIp3 Streams

Updated under an hour ago (Oct 28, 2026, 6:23 AM ET)

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Every CVE for bytecodealliance wasmtime

Exploited in the last 30 days

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.

CVSS: 5.8 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H
Weakness (CWE): CWE-770
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Oct 22, 2026
First seen by InfoSec Signals: Oct 22, 2026

Affected products

Affected products

bytecodealliance wasmtime bytecodealliance:wasmtime (from the name)	from 46.0.0 before 46.0.3; 46.0.3 not affected; from 47.0.0 before 47.0.4; 47.0.4 not affected	CNA record

References

References

https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-x84v-gj2h-g759	vendor-advisory
https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-46.0.3-and-47.0.0-before-47.0.4-unbounded-heap-allocation-via-wasip3-streams	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.