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CVE Record

CVE-2026-44216: Wasmtime: Panic when allocating a table exceeding the size of the host's address space

Wasmtime is a runtime for WebAssembly. From 30.0.0 to 36.0.8, 43.0.2, and 44.0.1, Wasmtime's allocation logic for a WebAssembly table contained checked arithmetic which panicked on overflow. This overflow is possible to trigger, and thus panic, when a table with an extremely large size is allocated. This is possible with the WebAssembly memory64 proposal where tables can have sizes in the 64-bit range as opposed to the previous 32-bit range which would not overflow. The panic happens when attempting to create a very large table, such as when instantiating a WebAssembly module or component. This vulnerability is fixed in 36.0.8, 43.0.2, and 44.0.1.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Wasmtime can crash when processing a WebAssembly module or component that requests an extremely large 64-bit table. Services accepting untrusted WebAssembly could lose availability, but the supplied sources do not indicate data theft or modification.

Executive priority

Prioritize internet-facing or multi-tenant services that execute untrusted WebAssembly. Patch promptly because a triggered panic can interrupt service without authentication. Internal, trusted-input deployments should still be inventoried and scheduled for upgrade after exposure is confirmed.

Technical view

Affected Wasmtime releases use checked arithmetic during table allocation that panics on overflow. WebAssembly memory64 permits table sizes large enough to trigger this condition during module or component instantiation. The reported impact is denial of service, scored CVSS 7.5.

Likely exposure

Exposure is highest where affected Wasmtime versions instantiate untrusted or remotely supplied WebAssembly with memory64 capabilities. Risk is lower when WebAssembly inputs are fully trusted or the vulnerable functionality is unreachable, but deployment-specific verification is required.

Exploitation context

The CVSS vector describes network-reachable, low-complexity, unauthenticated availability impact without user interaction. However, CISA KEV status is false, and the supplied sources provide no evidence of active exploitation. Actual remote reachability depends on how Wasmtime is integrated.

Researcher notes

The weakness combines integer overflow handling and excessive allocation behavior, mapped to CWE-190 and CWE-770. The supplied evidence establishes a triggerable panic and availability impact, not memory corruption, confidentiality loss, or integrity compromise. Assess process isolation and restart behavior when estimating operational impact.

Mitigation direction

  • Upgrade 30.x through 36.x deployments to Wasmtime 36.0.8 or a vendor-confirmed later unaffected release.
  • Upgrade 37.x through 43.x deployments to Wasmtime 43.0.2 or a vendor-confirmed later unaffected release.
  • Upgrade Wasmtime 44.0.0 to 44.0.1 or a vendor-confirmed later unaffected release.
  • Restrict untrusted WebAssembly ingestion until affected runtimes are remediated.
  • Apply relevant downstream vendor updates, including applicable Red Hat errata.

Validation and detection

  • Inventory direct and transitive Wasmtime versions across applications, containers, build manifests, and deployed artifacts.
  • Confirm no deployment runs the listed affected version ranges.
  • Identify services that instantiate externally supplied WebAssembly modules or components.
  • Review whether memory64 and 64-bit table allocation paths are reachable.
  • Check runtime logs and crash telemetry for table-allocation panics or unexplained availability failures.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-190: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-770: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-44216 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADP
5.9CVSS 4.0MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

5.9Medium
CVSS 4.0 vector shape for CVE-2026-44216Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPwasmtime: Wasmtime: Denial of Service via large WebAssembly table allocation
other:Red Hat severity ratingcvssV3_1
  • 2026-05-14T16:01:38.636Z: Reported to Red Hat.
  • 2026-05-14T14:54:32.975Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
bytecodealliancewasmtime>= 30.0.0, < 36.0.8, >= 37.0.0, < 43.0.2, 44.0.0Listed
Weakness

CWE details

CWE-190CWE-770

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-190 · source CWE mapping

Integer Overflow or Wraparound

Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-770 · source CWE mapping

Allocation of Resources Without Limits or Throttling

Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs