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TI-2026-79474 Aliases CVE-2026-115389GHSA-3g9q-2gmg-4cvp

Wasmtime Denial of Service via Val API

Priority LOW 6CWE-770Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
Low
User interaction
Passive
Attack complexity
High
Attack requirements
Present
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-770.

Summary

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not account for host allocations when lifting guest values through the dynamically-typed Val API, which bypasses the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing a denial of service (CWE-770). CVSS 4.0 scores it 1.0 (LOW), and Red Hat rates it Low.

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

Description from the CNA

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing denial of service.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00153 4th percentileScored 2026-11-07
Fix Partial wasmtime (bytecodealliance): 36.0.16, 48.0.3, 49.0.1Red Hat: 2 without a fix

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 36.0.16, 48.0.3, or 49.0.1, depending on the release line in use. Red Hat Connectivity Link 1 and Red Hat Enterprise Linux 10 have no fix available yet.

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-2026-79473 Unbounded writes in Wasmtime WASI HTTP exhaust host memoryPriority LOW 29
    • TI-2026-79472 Host panic in Wasmtime WASI filesystem timestamp handlingPriority LOW 29
    Show all 3 records →

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Connectivity Link 1AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-115389
  2. 2026-10-22 Alias added: GHSA-3g9q-2gmg-4cvp
  3. 2026-10-23 Affected versions changed · Red Hat
  4. 2026-10-23 CVSS score added · Red Hat
  5. 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