GHSA-h84q-m8rr-3v9q CVE-2022-39394 RUSTSEC-2022-0097
wasmtime_trap_code C API function has out of bounds write vulnerability
Critical
crates.io
- Severity
- 3.8 / 10
- Critical · CVSS 3.1
- Exploit chance (EPSS)
- 0.35%
- Chance of exploitation in the next 30 days. Higher than 29.16% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-787 Out-of-bounds Write
- Fix
2.0.2- Upgrade wasmtime to this version or later
Description
Impact
There is a bug in Wasmtime's C API implementation where the definition of the wasmtime_trap_code does not match its declared signature in the wasmtime/trap.h header file. This discrepancy causes the function implementation to perform a 4-byte write into a 1-byte buffer provided by the caller. This can lead to three zero bytes being written beyond the 1-byte location provided by the caller.
Patches
This bug has been patched and users should upgrade to Wasmtime 2.0.2.
Workarounds
This can be worked around by providing a 4-byte buffer casted to a 1-byte buffer when calling wasmtime_trap_code. Users of the wasmtime crate are not affected by this issue, only users of the C API function wasmtime_trap_code are affected.
References
For more information
If you have any questions or comments about this advisory:
- Reach out to us on the Bytecode Alliance Zulip chat
- Open an issue in the bytecodealliance/wasmtime repository
Affected versions
crates.io
| Package | Vulnerable | Fixed in |
|---|---|---|
| wasmtime | >= 2.0.0, < 2.0.2 |
2.0.2 |
| wasmtime | < 1.0.2 |
1.0.2 |
| wasmtime | >= 0.0.0-0, < 1.0.2>= 2.0.0, < 2.0.2 |
1.0.22.0.2 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
wasmtime crates.io → 2.0.2
- cargo
cargo update -p wasmtime --precise 2.0.2
Severity breakdown
CVSS 3.1 3.8
CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:L
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- High
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Weakness
CWE-787: Out-of-bounds Write
The product writes data past the end, or before the beginning, of the intended buffer.
How to prevent it
- Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.
- Operation, Build and Compilation: Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
- Implementation: Consider adhering to the following rules when allocating and managing an application's memory: Double check that the buffer is as large as specified. When using functions that accept a number of bytes to copy, such as strncpy(), be aware that if the destination buffer size is equal to the source buffer size, it may not NULL-terminate the string. Check buffer boundaries if accessing the buffer in a loop and make sure there is no danger of writing past the allocated space. If necessary, truncate all input strings to a reasonable length before passing them to the copy and concatenation functions.
- Operation, Build and Compilation: Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking. For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
- Operation: Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].
- Implementation: Replace unbounded copy functions with analogous functions that support length arguments, such as strcpy with strncpy. Create these if they are not available.
References
Advisories
Packages
Other links
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-h84q-m8rr-3v9q
- github.com/bytecodealliance/wasmtime/commit/087d9d7becf7422b3f872a3bcd5d97bb7ce…
- github.com/bytecodealliance/wasmtime/commit/5b6d5e78de106503b3b9add218bb3d2b1d6…
- groups.google.com/a/bytecodealliance.org/g/sec-announce/c/c1HBDDJwNPA
- rustsec.org/advisories/RUSTSEC-2022-0097.html
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| RUSTSEC-2026-0424 Unchecked memory usage in transferring borrowed resources between components | Not rated yet | Also affects wasmtime |
| RUSTSEC-2026-0423 Cross-engine type confusion with host-created struct-types-with-supertypes | Not rated yet | Also affects wasmtime |
| RUSTSEC-2026-0422 Typed functions with `i31` or `nullref` arguments may panic due to insufficient type-check | Low | Also affects wasmtime |
| RUSTSEC-2026-0379 Wasmtime: Cranelift backend on aarch64 can jump to incorrect target on large Wasm `br_table` instruction | Critical | Also affects wasmtime |
| GHSA-9pvw-hwfg-92h5 Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type | Medium | Also affects wasmtime |
| GHSA-897f-g5gm-fmxm Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation | Critical | Also affects wasmtime |
| RUSTSEC-2026-0364 Exception tags can cause host data structures to be unaligned | Not rated yet | Also affects wasmtime |
| RUSTSEC-2026-0363 Component-model handle tables are capped only per instance and charged to no limit | Medium | Also affects wasmtime |
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