CVE-2026-27572

MEDIUM EPSS 37.0%
Published Feb 24, 20264mo ago · Modified Jun 17, 20261w ago
6.9 CVSS 4.0
Medium
Find Similar
Published Feb 24, 2026 4mo ago
Last Modified Jun 17, 2026 1w ago

Description

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of the `wasi:http/types.fields` resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime's implementation in the `wasmtime-wasi-http` crate is backed by a data structure which panics when it reaches excessive capacity and this condition was not handled gracefully in Wasmtime. Panicking in a WASI implementation is a Denial of Service vector for embedders and is treated as a security vulnerability in Wasmtime. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 patch this vulnerability and return a trap to the guest instead of panicking. There are no known workarounds at this time. Embedders are encouraged to update to a patched version of Wasmtime.

CVSS Details

Base Score
6.9
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction P
Scope X

Threat Intelligence

EPSS Exploit Probability
37.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-770

Affected Products 4

VendorProductVersionRange
bytecodealliancewasmtime* <24.0.6
bytecodealliancewasmtime*≥25.0.0  –  <36.0.6
bytecodealliancewasmtime*≥37.0.0  –  <40.0.4
bytecodealliancewasmtime*≥41.0.0  –  <41.0.4

References 7

  • docs.rs https://docs.rs/http/1.4.0/http/header/#limitations
    Not Applicable
  • github.com https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a
    Patch
  • github.com https://github.com/bytecodealliance/wasmtime/releases/tag/v24.0.6
    ProductRelease Notes
  • github.com https://github.com/bytecodealliance/wasmtime/releases/tag/v36.0.6
    ProductRelease Notes
  • github.com https://github.com/bytecodealliance/wasmtime/releases/tag/v40.0.4
    ProductRelease Notes
  • github.com https://github.com/bytecodealliance/wasmtime/releases/tag/v41.0.4
    ProductRelease Notes
  • github.com https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-243v-98vx-264h
    Third Party Advisory

Remediation

  • github.com https://github.com/bytecodealliance/wasmtime/commit/301dc7162cca51def19131019af1187f45901c0a
    Patch