Medium severity · published Oct 29, 2026
CVE-2026-119143
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Panic via Zero-Length Stream Writes
New
4.8
CVSS
–
EPSS
No
On KEV
Description
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a denial of service vulnerability that allows guest code to trigger a host panic through out-of-bounds zero-length stream operations. Malicious guests can perform zero-length component model stream reads or writes with unvalidated addresses, causing Direct{Source,Destination}::remaining to panic and crash WASIp3 embedders.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
Required
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WA
wasmtime · bytecodealliance
46.0.0 before 48.0.6; 49.0.0 before 49.0.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-119143
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-119143
vendor-advisory
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-93g3-36p8-x2gc
third-party-advisory
https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.6-and-49.0.0-before-49.0.3-panic-via-zero-length-stream-writes
More from wasmtime
10.0
CVE-2024-51745
Wasmtime doesn't fully sandbox all the Windows device filenames
9.9
CVE-2026-115893
Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction
9.9
CVE-2026-115889
Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation
9.9
CVE-2026-115384
Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 Stack Buffer Overflow
9.9
CVE-2026-34987
Wasmtime with Winch compiler backend on aarch64 may allow a sandbox-escaping memory access