Wasmtime wasi:http zero timeout causes host panic
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
Wasmtime from 46.0.0 before 48.0.4 and from 49.0.0 before 49.0.2 has a wasi:http implementation that does not validate a zero between-bytes timeout request option (CWE-1284). The value is passed directly to a Tokio API that panics, which crashes the host embedding. An attacker who controls a guest module, with low privileges and some user interaction, can cause this denial of service.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
Wasmtime 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a denial-of-service vulnerability in its wasi:http implementation that allows guests to panic the host. Guests can specify a zero between-bytes-timeout request option, which is forwarded directly to a Tokio API that panics, crashing the host embedding.
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 | 46.0.0 to before 48.0.4; 49.0.0 to before 49.0.2 | 48.0.4, 49.0.2 | Patch available | CNA |
- wasmtime Vendorbytecodealliance Affected 46.0.0 to before 48.0.4; 49.0.0 to before 49.0.2 Fixed in 48.0.4, 49.0.2 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 48.0.4 or 49.0.2. Red Hat lists Red Hat Connectivity Link 1 and Red Hat Enterprise Linux 10 as affected, with no plan available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
- Fix · CNA wasmtime (bytecodealliance) Fixed in 48.0.4, 49.0.2
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
bytecodealliance wasmtime 48.0.4, 49.0.2
5 records Highest priority Priority MEDIUM 1 MEDIUM, 4 LOW
Other records, highest priority first
- TI-2026-79469 Stack buffer overflow in Wasmtime async callbacksPriority MEDIUM 42
- TI-2026-79464 Missing GC rooting in Wasmtime try_call corrupts GC heapPriority LOW 30
- TI-2026-79470 Host panic in Wasmtime WASIp3 timestamp handlingPriority LOW 29
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Connectivity Link 1 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-22 Threatist record created from CVE-2026-115382
- 2026-10-22 Alias added: GHSA-5gfg-32ph-pxg9
- 2026-10-23 Affected versions changed · Red Hat
- 2026-10-23 CVSS score added · Red Hat
- 2026-10-23 Priority changed: MEDIUM → LOW
- 2026-10-23 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-2026-115382 · CVE Program
- CVE-2026-115382 · NVD
- FIRST EPSS
- GHSA-5gfg-32ph-pxg9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-115382 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences