Stream: git-wasmtime

Topic: wasmtime / issue #15014 RUSTSEC-2026-0400: Use-after-free...

view this post on Zulip Wasmtime GitHub notifications bot (Oct 27 2026 at 00:13):

github-actions[bot] opened issue #15014:

Use-after-free of a dictionary after a one-shot call on a context with an open stream

Details
Status unsound
Package zstd-safe
Version 5.0.2+zstd.1.5.2
URL https://github.com/gyscos/zstd-rs/commit/d34502a0ed07f80ab2aa4c65059578e0466f2467
Date 2026-10-16

The one-shot DCtx and CCtx methods assumed the C library resets the
context, but it leaves an open stream as it is. When a stream was left
unfinished on a context, a one-shot call such as decompress_using_dict
could leave the context pointing at the dictionary borrowed for that call,
and the next streaming call resumed the stream against it after it was
freed: decompressed output then contained freed heap memory. On the
compression side, the stream resumed against the one-shot call's buffers.

This requires an application to use one context for both streaming and
one-shot calls without a reset in between. The flaw was corrected by
resetting the session after one-shot calls whenever a stream may be open.

See advisory page for additional details.

view this post on Zulip Wasmtime GitHub notifications bot (Oct 27 2026 at 00:39):

pchickey closed issue #15014:

Use-after-free of a dictionary after a one-shot call on a context with an open stream

Details
Status unsound
Package zstd-safe
Version 5.0.2+zstd.1.5.2
URL https://github.com/gyscos/zstd-rs/commit/d34502a0ed07f80ab2aa4c65059578e0466f2467
Date 2026-10-16

The one-shot DCtx and CCtx methods assumed the C library resets the
context, but it leaves an open stream as it is. When a stream was left
unfinished on a context, a one-shot call such as decompress_using_dict
could leave the context pointing at the dictionary borrowed for that call,
and the next streaming call resumed the stream against it after it was
freed: decompressed output then contained freed heap memory. On the
compression side, the stream resumed against the one-shot call's buffers.

This requires an application to use one context for both streaming and
one-shot calls without a reset in between. The flaw was corrected by
resetting the session after one-shot calls whenever a stream may be open.

See advisory page for additional details.

Last updated: Oct 31 2026 at 23:03 UTC