[36.0.x] Backport fixes for security advisories#12648
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alexcrichton merged 3 commits intoFeb 24, 2026
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This commit contains merged backports for two security advisories in Wasmtime: * GHSA-852m-cvvp-9p4w * GHSA-243v-98vx-264h This introduces new knobs to Wasmtime to limit the scope of resources that WASI implementations will allocate on behalf of guests. To preserve backwards-compatible behavior all knobs are set quite high (e.g. 2GiB). Embeddings can turn these knobs as appropriate to limit the amount of data the host will allocate for a guest. The following CLI knobs have been added: * `-Smax-resources` - limits the total component-model resources a guest can allocate in a table * `-Shostcall-fuel` - a broad limit which enforces that at most this amount of data will be copied from the guest to the host in any one API call (e.g. `string` values can't be too big, `list<string>` can't be quadratic, etc). This fuel is reset on each host function call. * `-Smax-random-size` - the maximal size of the return value of the `get-random-bytes` and `get-insecure-random-bytes` WASI functions. * `-Smax-http-fields-size` - a limit on the size of `wasi:http` `fields` values to avoid infinitely buffering data within the host. The `http` crate has additionally been updated to avoid a panic when adding too many headers to a `fields` object. Co-authored-by: Mark Bundschuh <mark@mbund.dev> Co-authored-by: Pat Hickey <p.hickey@f5.com>
dicej
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Feb 24, 2026
alexcrichton
merged commit 48b427b
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bytecodealliance:release-36.0.0
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This commit contains merged backports for two security advisories in Wasmtime:
This introduces new knobs to Wasmtime to limit the scope of resources that WASI implementations will allocate on behalf of guests. To preserve backwards-compatible behavior all knobs are set quite high (e.g. 2GiB). Embeddings can turn these knobs as appropriate to limit the amount of data the host will allocate for a guest. The following CLI knobs have been added:
-Smax-resources- limits the total component-model resources a guest can allocate in a table-Shostcall-fuel- a broad limit which enforces that at most this amount of data will be copied from the guest to the host in any one API call (e.g.stringvalues can't be too big,list<string>can't be quadratic, etc). This fuel is reset on each host function call.-Smax-random-size- the maximal size of the return value of theget-random-bytesandget-insecure-random-bytesWASI functions.-Smax-http-fields-size- a limit on the size ofwasi:httpfieldsvalues to avoid infinitely buffering data within the host.The
httpcrate has additionally been updated to avoid a panic when adding too many headers to afieldsobject.