Critical severity · published Oct 23, 2026
CVE-2026-115893
Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
New
9.9
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 37% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WA
wasmtime · bytecodealliance
< 36.0.19; >= 37.0.0, < 48.0.7; >= 49.0.0, < 49.0.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-115893
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-115893
github.com
https://github.com/bytecodealliance/wasmtime/commit/222ff3a65dab9aa7011f8c246937751a0bac5abd
github.com
https://github.com/bytecodealliance/wasmtime/commit/994549891c8a706cb4f2809f9d17b9f67b31e618
github.com
https://github.com/bytecodealliance/wasmtime/commit/e61df1b454be9313d61a5f8de07722a421139bbe
github.com
https://github.com/bytecodealliance/wasmtime/commit/f517bd6e890c7c1291ab9fe05d8cc0c9f11e56aa
github.com
https://github.com/bytecodealliance/wasmtime/pull/14818
github.com
https://github.com/bytecodealliance/wasmtime/pull/14819
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