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Fencer Intel
high 8.1

CVE-2022-24791 json

Use after free in Wasmtime

published 4y ago modified 28d ago also GHSA-gwc9-348x-qwv2 , RUSTSEC-2022-0016 , RUSTSEC-2022-0099 , EUVD-2022-1747

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits
0
none known

Summary

Wasmtime is a standalone JIT-style runtime for WebAssembly, using Cranelift. There is a use after free vulnerability in Wasmtime when both running Wasm that uses externrefs and enabling epoch interruption in Wasmtime. If you are not explicitly enabling epoch interruption (it is disabled by default) then you are not affected. If you are explicitly disabling the Wasm reference types proposal (it is enabled by default) then you are also not affected. The use after free is caused by Cranelift failing to emit stack maps when there are safepoints inside cold blocks. Cold blocks occur when epoch interruption is enabled. Cold blocks are emitted at the end of compiled functions, and change the order blocks are emitted versus defined. This reordering accidentally caused Cranelift to skip emitting some stack maps because it expected to emit the stack maps in block definition order, rather than block emission order. When Wasmtime would eventually collect garbage, it would fail to find live references on the stack because of the missing stack maps, think that they were unreferenced garbage, and therefore reclaim them. Then after the collection ended, the Wasm code could use the reclaimed-too-early references, which is a use after free. Patches have been released in versions 0.34.2 and 0.35.2, which fix the vulnerability. All Wasmtime users are recommended to upgrade to these patched versions. If upgrading is not an option for you at this time, you can avoid the vulnerability by either: disabling the Wasm reference types proposal, config.wasm_reference_types(false); or by disabling epoch interruption if you were previously enabling it. config.epoch_interruption(false).

Patch / fix

  • crates.io wasmtime 0.34.2, 0.35.2
  • bytecodealliance wasmtime 0.34.2, 0.35.2
  • firefox Ubuntu 22.04 LTS 1:1snap1-0ubuntu1

ubuntu advisories UBUNTU-CVE-2022-24791

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • cargo-audit-advisory-db openSUSE Tumbleweed 20220420-1.1

opensuse advisories openSUSE-SU-2024:12009-1

Is CVE-2022-24791 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
last yr.

Exploit prediction

1.18% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
crates.io wasmtime
<0.34.2
>=0.35.0, <0.35.2
>=0.0.0-0, <0.34.2
>=0.34.0, <0.34.2
0.34.2
0.35.2

Affected products

  • bytecodealliance wasmtime

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.