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Fencer Intel
critical 9.9

CVE-2026-115893 json

Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction

published 21d ago modified 11d ago also EUVD-2026-109188 , GHSA-mghf-wjfp-p5xm , RUSTSEC-2026-0379

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19, 48.0.7, and 49.0.4, the Cranelift compiler backend on aarch64 can compile a Wasm br_table instruction with more than approximately 256,000 targets so that it has an incorrect conditional branch target. The branch can then jump to arbitrary other code at a user-controlled offset, allowing a user-controlled Wasm module to escape the sandbox on aarch64 engines using the default Cranelift backend. This issue is fixed in versions 36.0.19, 48.0.7, and 49.0.4.

Patch / fix

  • crates.io wasmtime 36.0.19, 48.0.7, 49.0.4
  • bytecodealliance wasmtime 36.0.19, 48.0.7, 49.0.4
  • rust-wasmtime Debian 14 36.0.20+dfsg-1

debian advisories DEBIAN-CVE-2026-115893

  • rust Azure Linux 3.0 1.75.0-31
  • rust Azure Linux 3.0 1.98.1-1

azure linux advisories AZL-111428AZL-111434

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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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-2026-115893 updated cvss 8.8

wasmtime: Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction

  • Red Hat Connectivity Link 1 rhcl-1/wasm-shim-rhel9 Red Hat Enterprise Linux 10 tree-sitter
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 10 virt-firmware-rs
    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
total
Assessed
11d ago

Exploit prediction

0.99% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
GitHub 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
OSV 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
crates.io wasmtime
<36.0.19
>=37.0.0, <48.0.7
>=49.0.0, <49.0.4
>=0.0.0-0, <36.0.19
36.0.19
48.0.7
49.0.4

Affected products

  • bytecodealliance wasmtime

Classification

Weakness
  • CWE-691 Insufficient Control Flow Management

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.