Resource exhaustion in Bytecodealliance Wasmtime
CVE-2026-115388
wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies, so oversized writes succeed instead of trapping. A malicious guest can pass large buffers to write on outgoing-body resources, holding host allocations for the store's lifetime and exhausting host memory.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.2 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-c9gc-w9vx-w86p (vendor-advisory)
- www.vulncheck.com/advisories/wasmtime-before-36.0.16-37.0.0-before-48.0.3-and-4… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-115388?
- CVE-2026-115388 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under Uncontrolled Resource Consumption. CVSS score: 6.2/10. Published 2026-10-22.
- How severe is CVE-2026-115388?
- Medium severity. CVSS v3 base score is 6.2 out of 10.