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Fencer Vulns
medium 4.8

CVE-2026-119135 json

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Panic via StreamReader Type Mismatch

published 2026-10-14 26 d ago modified 2026-11-04 5 d ago also EUVD-2026-113202 , GHSA-63h4-6cx9-pjfj , RUSTSEC-2026-0355

cvss
4.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

Summary

Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 panics when the host reads a component model stream as a different Rust item type than it was created with, because the host-to-host read path asserts matching TypeIds instead of returning an error. Guest code can return a host-created StreamReader<U> that the embedder reads as StreamReader<T>, where both types map to the same component model type, crashing the embedding process.

Patch / fix

  • crates.io wasmtime 48.0.6, 49.0.3
  • bytecodealliance wasmtime 48.0.6, 49.0.3

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-119135 updated cvss 4.8

wasmtime: Wasmtime: Denial of Service via component stream type mismatch

  • Red Hat Connectivity Link 1 rhcl-1/wasm-shim-rhel9 Red Hat Enterprise Linux 10 tree-sitter 0.23.0-3.el10, virt-firmware-rs 26.4-1.el10
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 d ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.9 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 3.1 4.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H
CNA 4.0 5.9 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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

Affected packages

ecosystem package affected fixed in
crates.io wasmtime
>=46.0.0, <48.0.6
>=49.0.0, <49.0.3
48.0.6
49.0.3

Affected products

  • bytecodealliance wasmtime

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.