Stream: git-wasmtime

Topic: wasmtime / PR #12649 [40.0.x] Backport fixes for security...

Wasmtime GitHub notifications bot (Feb 24 2026 at 16:33):

alexcrichton opened PR #12649 from alexcrichton:back40 to bytecodealliance:release-40.0.0:

This commit contains merged backports for three security advisories in Wasmtime:

• GHSA-852m-cvvp-9p4w
• GHSA-243v-98vx-264h
• GHSA-xjhv-v822-pf94

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. Finally, a panic when dropping {Typed,}Func::call_async has been resolved when the component-model-async feature is enabled at compile time.

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Wasmtime GitHub notifications bot (Feb 24 2026 at 16:33):

alexcrichton requested wasmtime-wasi-reviewers for a review on PR #12649.

Wasmtime GitHub notifications bot (Feb 24 2026 at 16:33):

alexcrichton requested fitzgen for a review on PR #12649.

Wasmtime GitHub notifications bot (Feb 24 2026 at 16:33):

alexcrichton requested wasmtime-default-reviewers for a review on PR #12649.

Wasmtime GitHub notifications bot (Feb 24 2026 at 16:33):

alexcrichton requested wasmtime-core-reviewers for a review on PR #12649.

Wasmtime GitHub notifications bot (Feb 24 2026 at 16:40):

dicej submitted PR review.

Wasmtime GitHub notifications bot (Feb 24 2026 at 16:44):

alexcrichton updated PR #12649.

Wasmtime GitHub notifications bot (Feb 24 2026 at 17:04):

alexcrichton updated PR #12649.

Wasmtime GitHub notifications bot (Feb 24 2026 at 17:46):

alexcrichton merged PR #12649.

Last updated: Mar 23 2026 at 16:19 UTC