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TI-2026-79476 Aliases CVE-2026-115391GHSA-6862-f859-6m9r

Wasmtime WASIp3 Streams Allow Unbounded Heap Allocation

Priority LOW 30CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
Present
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-770.

Summary

Wasmtime from 46.0.0 before 46.0.3 and from 47.0.0 before 47.0.4 contains an allocation of resources without limits (CWE-770) in its WASIp3 implementation. The host buffers guest-specified-length writes to WASIp3 file or HTTP write streams without limit. A malicious guest that offers large buffers can exhaust host memory. Exploitation requires low privileges and passive user interaction, and the impact is limited to availability.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

Wasmtime 46.0.0 before 46.0.3 and 47.0.0 before 47.0.4 contains an uncontrolled resource allocation vulnerability in its WASIp3 implementation that buffers guest-specified-length writes on the host without limit. Malicious guests can offer large buffers to WASIp3 file or HTTP write streams, causing the host to copy and buffer all bytes, bounded only by guest linear memory, exhausting host memory.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00172 6th percentileScored 2026-11-07
Fix Fixed wasmtime (bytecodealliance): 46.0.3, 47.0.4

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

VendorProductAffected versionsFixed inStatusSource
bytecodealliancewasmtime46.0.0 to before 46.0.3; 47.0.0 to before 47.0.446.0.3, 47.0.4Patch availableCNA
  • wasmtime Vendorbytecodealliance Affected 46.0.0 to before 46.0.3; 47.0.0 to before 47.0.4 Fixed in 46.0.3, 47.0.4 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:*——bytecodealliance
  • cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:*:*:* Versions — — ·bytecodealliance

Remediation

Upgrade Wasmtime to version 46.0.3 or 47.0.4, which fix the issue. Red Hat rates the issue Moderate.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

  • Fix · CNA wasmtime (bytecodealliance) Fixed in 46.0.3, 47.0.4

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 2 products
  • Red Hat Connectivity Link 1
  • Red Hat Enterprise Linux 10

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-115391
  2. 2026-10-22 Alias added: GHSA-6862-f859-6m9r
  3. 2026-10-23 Affected versions changed · Red Hat
  4. 2026-10-23 CVSS score added · Red Hat
  5. 2026-10-23 Priority changed: MEDIUM → LOW
  6. 2026-10-24 Affected versions changed · Red Hat
  7. 2026-11-04 CISA SSVC decision points changed

References

Advisory 1

  • 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
See all 97 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences