Skip to content
Fencer Intel
medium 5.8

CVE-2026-115391 json

Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 Unbounded Heap Allocation via WASIp3 Streams

published 2mo ago modified 5d ago also EUVD-2026-108324 , GHSA-x84v-gj2h-g759 , RUSTSEC-2026-0268

cvss
5.8
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 6%
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io wasmtime 46.0.3, 47.0.4
  • bytecodealliance wasmtime 46.0.3, 47.0.4

Is CVE-2026-115391 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2026-115391 updated cvss 5.8

wasmtime: wasmtime: Denial of Service via unbounded buffering in WASIp3 write streams

  • 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
    not affected: vulnerable code not present

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
5d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 6.9 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
CNA 3.1 5.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:N/A:H
CNA 4.0 6.9 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

Affected packages

ecosystem package affected fixed in
crates.io wasmtime
>=46.0.0, <46.0.3
>=47.0.0, <47.0.4
46.0.3
47.0.4

Affected products

  • bytecodealliance wasmtime

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Intel 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.