CVE-2026-126406: Wasmtime before 36.0.20 HTTP Request Smuggling via wasi-http p2 Content-Length
bytecodealliance · wasmtime
Vendor fix available · Affected: bytecodealliance wasmtime · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 16% of scored CVEs
DescriptionCVE.org
The wasmtime-wasi-http p2 implementation in Wasmtime before 36.0.20, 37.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 can send conflicting content-length headers, or ones not matching the body, in outgoing requests. A guest that reuses a received response's headers resource to send a bodyless request can enable request smuggling against non-compliant servers, potentially bypassing embedder destination access controls.
Affected products4
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- bytecodealliance · wasmtimebefore 36.0.20
- bytecodealliance · wasmtimefrom 37.0.0 before 48.0.8
- bytecodealliance · wasmtimefrom 49.0.0 before 49.0.5
- bytecodealliance · wasmtimefrom 50.0.0 before 50.0.1
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- bytecodealliance
- Published
- November 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-126406 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.