Host panic in Wasmtime WASI filesystem timestamp handling
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-190 and the CVSS impact.
Summary
Wasmtime before 36.0.16, from 37.0.0 before 48.0.3, and from 49.0.0 before 49.0.1 contains a denial of service flaw in wasmtime-wasi. An integer overflow (CWE-190) occurs when filesystem timestamps have a sub-second field that overflows the seconds field, which crashes the host. A local guest WASI program with no privileges and no user interaction can trigger it.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Description from the CNA
Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 contains a denial of service vulnerability in wasmtime-wasi that allows guest WASI programs to panic the host via overflowing filesystem timestamps. Attackers can pass atim or mtim values whose sub-second field overflows the seconds field to path_filestat_set_times, fd_filestat_set_times, set-times, or set-times-at, crashing the host.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| bytecodealliance | wasmtime | before 36.0.16; 37.0.0 to before 48.0.3; 49.0.0 to before 49.0.1 | 36.0.16, 48.0.3, 49.0.1 | Patch available | CNA |
- wasmtime Vendorbytecodealliance Affected before 36.0.16; 37.0.0 to before 48.0.3; 49.0.0 to before 49.0.1 Fixed in 36.0.16, 48.0.3, 49.0.1 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:* | — | — | bytecodealliance |
- cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:* Versions — — ·bytecodealliance
Remediation
Upgrade Wasmtime to 36.0.16, 48.0.3 or 49.0.1, matching the release line in use.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
- Fix · CNA wasmtime (bytecodealliance) Fixed in 36.0.16, 48.0.3, 49.0.1
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
bytecodealliance wasmtime 36.0.16, 48.0.3, 49.0.1
3 records Highest priority Priority LOW 3 LOW
Other records, highest priority first
- TI-2026-79473 Unbounded writes in Wasmtime WASI HTTP exhaust host memoryPriority LOW 29
- TI-2026-79474 Wasmtime Denial of Service via Val APIPriority LOW 6
Timeline
- 2026-10-22 Threatist record created from CVE-2026-115387
- 2026-10-22 Alias added: GHSA-xxx8-c5qx-wvm3
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-11-04 CISA SSVC decision points changed
References
More bytecodealliance vulnerabilities
- TI-2026-85541 WAMR fast interpreter loader heap overflow via constant deduplication mismatch CVSS 4.0HIGH 8.8
- TI-2024-16741 An issue in bytecodealliance wasm-micro-runtime before v.b3f728c and fixed in commit… CVSS 3.1HIGH 8.8
- TI-2024-22658 An out-of-bound memory read vulnerability was discovered in Bytecode Alliance… CVSS 3.1HIGH 7.5
- TI-2024-18300 wasm-micro-runtime (aka WebAssembly Micro Runtime or WAMR) 06df58f is vulnerable to NULL… CVSS 3.1HIGH 7.5
- TI-2023-26034 An heap overflow vulnerability was discovered in Bytecode alliance wasm-micro-runtime… CVSS 3.1HIGH 7.5
- TI-2025-33969 WebAssembly Micro Runtime's `--addr-pool` option allows all IPv4 addresses when subnet mask is not specified CVSS 4.0MEDIUM 6.9
Sources
- CVE-2026-115387 · CVE Program
- CVE-2026-115387 · NVD
- FIRST EPSS
- GHSA-xxx8-c5qx-wvm3 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences