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No exploitation reportedFix available

CVE-2026-27204

Wasmtime WASI implementations are vulnerable to guest-controlled resource exhaustion

No exploitation reported by the sources we read.

  • Published2026-02-24
  • Fixed in41.0.4 · 40.0.4 · 36.0.6 · 24.0.6
  • WeaknessCWE-400 · CWE-770 · CWE-774

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of WASI host interfaces are susceptible to guest-controlled resource exhaustion on the host. Wasmtime did not appropriately place limits on resource allocations requested by the guests. This serves as a Denial of Service vector. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 have all been released with the fix for this issue. These versions do not prevent this issue in their default configuration to avoid breaking preexisting behaviors. All versions of Wasmtime have appropriate knobs to prevent this behavior, and Wasmtime 42.0.0-and-later will have these knobs tuned by default to prevent this issue from happening. There are no known workarounds for this issue without upgrading. Embedders are recommended to upgrade and configure their embeddings as necessary to prevent possibly-malicious guests from triggering this issue.

Timeline

dates in UTC
  1. 2026-02-2422:16CVE publishedNVD

Versions per branch

NVD · OSV
Bytecodealliance wasmtime
BranchAffectedFixed in
41.0≥ 41.0.0, < 41.0.441.0.4
40.0≥ 37.0.0, < 40.0.440.0.4
36.0≥ 25.0.0, < 36.0.636.0.6
24.0< 24.0.624.0.6
24.0≥ 0.0.0-0, < 24.0.624.0.6

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • bytecodealliance wasmtime
    Affected
    • = < 24.0.6no fix stated
    • = >= 25.0.0, < 36.0.6no fix stated
    • = >= 37.0.0, < 40.0.4no fix stated
    • = >= 41.0.0, < 41.0.4no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-02-24

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • rust-wasmtimeUbuntu:26.10all versions · no fixed version listed
  • rust-wasmtimeUbuntu:26.04:LTSall versions · no fixed version listed
  • rust-wasmtimeUbuntu:25.10all versions · no fixed version listed
  • rust-wasmtimeUbuntu:24.04:LTSall versions · no fixed version listed
  • rust-wasmtimeDebian:14all versions · fixed in 36.0.6+dfsg-1
  • rust-wasmtimeDebian:13all versions · no fixed version listed
  • washWolfiall versions · no fixed version listed
  • washChainguardall versions · no fixed version listed

11 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-27204 Red Hat Product Security1 known affected

    wasmtime: Wasmtime: Denial of Service via guest-controlled resource exhaustion in WASI host interfaces

    rhcl-1/wasm-shim-rhel9 as a component of Red Hat Connectivity Link 1

Full record on NVD

Fix

  1. Update Bytecodealliance wasmtime to 41.0.4 · 40.0.4 · 36.0.6 · 24.0.6
  2. Workaround from the vendor Red Hat Product Security CVE-2026-27204 · 1 productMitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
  3. No fix available, says the vendor Red Hat Product Security CVE-2026-27204 · 1 productFix deferred

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionnone2026-02-27
  • CNACVSS 4.06.9known since 2026-10-23
  • NVDCVSS 3.16.5read 2026-10-23
  • CNAweakness (CWE)CWE-400, CWE-770, CWE-774, CWE-789known since 2026-10-23
  • NVDweakness (CWE)CWE-770read 2026-10-23
  • FIRST EPSSEPSS score0.4 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2026-02-24

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 4.0 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:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-02-24
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-852m-cvvp-9p4w

Frequently asked questions

What is CVE-2026-27204?

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of WASI host interfaces are susceptible to guest-controlled resource exhaustion on the host. Wasmtime did not appropriately place limits on resource allocations requested by the guests. This serves as a Denial of Service vector. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 have all been released with the fix for this issue. These versions do not prevent this issue in their default configuration to avoid breaking preexisting behaviors. All versions of Wasmtime have appropriate knobs to prevent this behavior, and Wasmtime 42.0.0-and-later will have these knobs tuned by default to prevent this issue from happening. There are no known workarounds for this issue without upgrading. Embedders are recommended to upgrade and configure their embeddings as necessary to prevent possibly-malicious guests from triggering this issue.

Is CVE-2026-27204 actively exploited?

Active exploitation of CVE-2026-27204 has not been confirmed. Its EPSS score was 0.4% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-27204?

CVE-2026-27204 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

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