https://cve.radiocsirt.org/rss/recent/all/10 Most recent entries from all 2026-10-04T01:17:59.143794+00:00 Vulnerability-Lookup csirt@opendfir.org python-feedgen Contains only the most 10 recent entries. https://cve.radiocsirt.org/vuln/euvd-2026-30521 EUVD-2026-30521 2026-10-04T01:17:59.256902+00:00 EUVD-2026-30521 https://cve.radiocsirt.org/vuln/fkie_cve-2021-39216 fkie_cve-2021-39216 2026-10-04T01:17:59.256945+00:00

Wasmtime is an open source runtime for WebAssembly & WASI. In Wasmtime from version 0.19.0 and before version 0.30.0 there was a use-after-free bug when passing `externref`s from the host to guest Wasm content. To trigger the bug, you have to explicitly pass multiple `externref`s from the host to a Wasm instance at the same time, either by passing multiple `externref`s as arguments from host code to a Wasm function, or returning multiple `externref`s to Wasm from a multi-value return function defined in the host. If you do not have host code that matches one of these shapes, then you are not impacted. If Wasmtime's `VMExternRefActivationsTable` became filled to capacity after passing the first `externref` in, then passing in the second `externref` could trigger a garbage collection. However the first `externref` is not rooted until we pass control to Wasm, and therefore could be reclaimed by the collector if nothing else was holding a reference to it or otherwise keeping it alive. Then, when control was passed to Wasm after the garbage collection, Wasm could use the first `externref`, which at this point has already been freed. We have reason to believe that the effective impact of this bug is relatively small because usage of `externref` is currently quite rare. The bug has been fixed, and users should upgrade to Wasmtime 0.30.0. If you cannot upgrade Wasmtime yet, you can avoid the bug by disabling reference types support in Wasmtime by passing `false` to `wasmtime::Config…

 https://cve.radiocsirt.org/vuln/ghsa-v4cp-h94r-m7xf GHSA-v4cp-h94r-m7xf — Use after free passing `externref`s to Wasm in Wasmtime 2026-10-04T01:17:59.256996+00:00

Affected: crates.io: wasmtime, PyPI: wasmtime

### Impact

There was a use-after-free bug when passing `externref`s from the host to guest Wasm content.

To trigger the bug, you have to explicitly pass multiple `externref`s from the host to a Wasm instance at the same time, either by

* passing multiple `externref`s as arguments from host code to a Wasm function, * or returning multiple `externref`s to Wasm from a multi-value return function defined in the host. If you do not have host code that matches one of these shapes, then you are not impacted.

If Wasmtime's [`VMExternRefActivationsTable`](https://github.com/bytecodealliance/wasmtime/blob/37c094faf53f1b356aab3c79d451395e4f7edb34/crates/runtime/src/externref.rs#L493) became filled to capacity after passing the first `externref` in, then passing in the second `externref` could trigger a garbage collection. However the first `externref` is not rooted until we pass control to Wasm, and therefore could be reclaimed by the collector if nothing else was holding a reference to it or otherwise keeping it alive. Then, when control was passed to Wasm after the garbage collection, Wasm could use the first `externref`, which at this point has already been freed.

We have reason to believe that the effective impact of this bug is relatively small because usage of `externref` is currently quite rare.

### Patches

The bug has been fixed, and users should upgrade to Wasmtime 0.30.0.

Additionally, we have updated [our primary `externref` fuzz target](https://github.com/bytecode…

 https://cve.radiocsirt.org/vuln/gsd-2021-39216 gsd-2021-39216 2026-10-04T01:17:59.257047+00:00 gsd-2021-39216 https://cve.radiocsirt.org/vuln/pysec-2021-320 PYSEC-2021-320 2026-10-04T01:17:59.257062+00:00

Affected: PyPI: wasmtime

Wasmtime is an open source runtime for WebAssembly & WASI. In Wasmtime from version 0.19.0 and before version 0.30.0 there was a use-after-free bug when passing `externref`s from the host to guest Wasm content. To trigger the bug, you have to explicitly pass multiple `externref`s from the host to a Wasm instance at the same time, either by passing multiple `externref`s as arguments from host code to a Wasm function, or returning multiple `externref`s to Wasm from a multi-value return function defined in the host. If you do not have host code that matches one of these shapes, then you are not impacted. If Wasmtime's `VMExternRefActivationsTable` became filled to capacity after passing the first `externref` in, then passing in the second `externref` could trigger a garbage collection. However the first `externref` is not rooted until we pass control to Wasm, and therefore could be reclaimed by the collector if nothing else was holding a reference to it or otherwise keeping it alive. Then, when control was passed to Wasm after the garbage collection, Wasm could use the first `externref`, which at this point has already been freed. We have reason to believe that the effective impact of this bug is relatively small because usage of `externref` is currently quite rare. The bug has been fixed, and users should upgrade to Wasmtime 0.30.0. If you cannot upgrade Wasmtime yet, you can avoid the bug by disabling reference types support in Wasmtime by passing `false` to `wasmtime::Config…

 https://cve.radiocsirt.org/vuln/rustsec-2021-0110 RUSTSEC-2021-0110 — Multiple Vulnerabilities in Wasmtime 2026-10-04T01:17:59.257095+00:00

Affected: crates.io: wasmtime

* [Use after free passing `externref`s to Wasm in Wasmtime](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-v4cp-h94r-m7xf)

* [Out-of-bounds read/write and invalid free with `externref`s and GC safepoints in Wasmtime](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-4873-36h9-wv49)

* [Wrong type for `Linker`-define functions when used across two `Engine`s](https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q879-9g95-56mx)