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TI-2026-79473 Aliases CVE-2026-115388GHSA-7qg7-h7wh-p6q8

Unbounded writes in Wasmtime WASI HTTP exhaust host memory

Priority LOW 29CWE-400Published · Updated

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-400.

Summary

The wasmtime-wasi-http component of Wasmtime before 36.0.16, from 37.0.0 before 48.0.3, and from 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies (CWE-400). Oversized writes succeed instead of trapping. A malicious guest with no privileges can pass large buffers to write on outgoing-body resources, which holds host allocations for the store's lifetime and can exhaust host memory.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

wasmtime-wasi-http in Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not enforce the wasi:io/streams check-write allowance for WASIp2 outgoing HTTP bodies, so oversized writes succeed instead of trapping. A malicious guest can pass large buffers to write on outgoing-body resources, holding host allocations for the store's lifetime and exhausting host memory.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00112 1st percentileScored 2026-11-07
Fix Fixed wasmtime (bytecodealliance): 36.0.16, 48.0.3, 49.0.1

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
bytecodealliancewasmtimebefore 36.0.16; 37.0.0 to before 48.0.3; 49.0.0 to before 49.0.136.0.16, 48.0.3, 49.0.1Patch availableCNA
  • 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.

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

Remediation

Upgrade Wasmtime to version 36.0.16, 48.0.3, or 49.0.1, matching the release line in use. The sources list no fixed version for wasmtime-wasi-http beyond these Wasmtime releases.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • 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-2026-79472 Host panic in Wasmtime WASI filesystem timestamp handlingPriority LOW 29
    • TI-2026-79474 Wasmtime Denial of Service via Val APIPriority LOW 6
    Show all 3 records →

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-115388
  2. 2026-10-22 Alias added: GHSA-7qg7-h7wh-p6q8
  3. 2026-10-23 Priority changed: MEDIUM → LOW
  4. 2026-10-29 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