vulnerability / NVI-00010746 / Revision 3
Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type
GitHub lists this reviewed advisory for wasmtime, wasmtime. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
0.434%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.3779. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
wasmtime
source listed>= 46.0.0, < 48.0.7
### Summary Wasmtime may panic when the host lowers a component model `stream` or `future` into a guest, if the host created that stream or future with one payload type and the guest expects a different one. This can happen when an embedder creates a stream or future, passes it through a guest, receives it back under a type-erased type such as `StreamAny` or `FutureAny`, and then passes it to a guest function with a different payload type. GHSA-63h4-6cx9-pjfj is a related advisory also fixing issues within this area, and this advisory is being issued for portions of Wasmtime that were not fixed as part of that advisory. ### Impact This affects embedders that do all of the following: 1. Create streams or futures on the host with `StreamReader::new` or `FutureReader::new` 2. Pass them to guest code and receive them back as `StreamAny`, `FutureAny`, `Val::Stream`/`Val::Future`, or a typed reader whose payload is one of these. 3. Pass them on to a guest function whose `stream` or `future` payload type differs from the type the host created them with. A guest can cause the mismatch in step 3 when it controls the types of the functions it exports or of the values it returns. In tha
wasmtime
source listed>= 49.0.0, < 49.0.4
### Summary Wasmtime may panic when the host lowers a component model `stream` or `future` into a guest, if the host created that stream or future with one payload type and the guest expects a different one. This can happen when an embedder creates a stream or future, passes it through a guest, receives it back under a type-erased type such as `StreamAny` or `FutureAny`, and then passes it to a guest function with a different payload type. GHSA-63h4-6cx9-pjfj is a related advisory also fixing issues within this area, and this advisory is being issued for portions of Wasmtime that were not fixed as part of that advisory. ### Impact This affects embedders that do all of the following: 1. Create streams or futures on the host with `StreamReader::new` or `FutureReader::new` 2. Pass them to guest code and receive them back as `StreamAny`, `FutureAny`, `Val::Stream`/`Val::Future`, or a typed reader whose payload is one of these. 3. Pass them on to a guest function whose `stream` or `future` payload type differs from the type the host created them with. A guest can cause the mismatch in step 3 when it controls the types of the functions it exports or of the values it returns. In tha
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-9pvw-hwfg-92h5 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-115892 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.