1. Home
  2. Vulnerabilities
  3. CVE-2026-27204
6.9
MEDIUM CVSS 4.0
CVE-2026-27204
Wasmtime WASI implementations are vulnerable to guest-controlled resource exhaustion
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.

INFO

Published Date :

Feb. 24, 2026, 10:16 p.m.

Last Modified :

Feb. 25, 2026, 3:20 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2026-27204 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Bytecodealliance wasmtime
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
CVSS 4.0 MEDIUM [email protected]
Solution
Upgrade Wasmtime to a fixed version and configure resource limits.
  • Upgrade Wasmtime to a patched version.
  • Configure resource allocation knobs to prevent exhaustion.
  • Tune resource knobs by default for Wasmtime 42.0.0+.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-27204.

URL Resource
https://docs.rs/wasmtime-wasi/latest/wasmtime_wasi/struct.WasiCtxBuilder.html#method.max_random_size Product
https://docs.rs/wasmtime/latest/wasmtime/component/struct.ResourceTable.html#method.set_max_capacity Product
https://docs.rs/wasmtime/latest/wasmtime/struct.Store.html#method.set_hostcall_fuel Product
https://docs.wasmtime.dev/security-what-is-considered-a-security-vulnerability.html Product
https://github.com/bytecodealliance/wasmtime/issues/11552 Issue Tracking
https://github.com/bytecodealliance/wasmtime/pull/12599 Issue Tracking Third Party Advisory
https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-852m-cvvp-9p4w Third Party Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-27204 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-27204 weaknesses.

CAPEC-147: XML Ping of the Death XML Ping of the Death CAPEC-227: Sustained Client Engagement Sustained Client Engagement CAPEC-492: Regular Expression Exponential Blowup Regular Expression Exponential Blowup CAPEC-125: Flooding Flooding CAPEC-130: Excessive Allocation Excessive Allocation CAPEC-147: XML Ping of the Death XML Ping of the Death CAPEC-197: Exponential Data Expansion Exponential Data Expansion CAPEC-229: Serialized Data Parameter Blowup Serialized Data Parameter Blowup CAPEC-230: Serialized Data with Nested Payloads Serialized Data with Nested Payloads CAPEC-231: Oversized Serialized Data Payloads Oversized Serialized Data Payloads CAPEC-469: HTTP DoS HTTP DoS CAPEC-482: TCP Flood TCP Flood CAPEC-486: UDP Flood UDP Flood CAPEC-487: ICMP Flood ICMP Flood CAPEC-488: HTTP Flood HTTP Flood CAPEC-489: SSL Flood SSL Flood CAPEC-490: Amplification Amplification CAPEC-491: Quadratic Data Expansion Quadratic Data Expansion CAPEC-493: SOAP Array Blowup SOAP Array Blowup CAPEC-494: TCP Fragmentation TCP Fragmentation CAPEC-495: UDP Fragmentation UDP Fragmentation CAPEC-496: ICMP Fragmentation ICMP Fragmentation CAPEC-528: XML Flood XML Flood

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-27204 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-27204 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Feb. 25, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-770
    Added CPE Configuration OR *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions up to (excluding) 24.0.6 *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions from (including) 25.0.0 up to (excluding) 36.0.6 *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions from (including) 37.0.0 up to (excluding) 40.0.4 *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions from (including) 41.0.0 up to (excluding) 41.0.4
    Added Reference Type GitHub, Inc.: https://docs.rs/wasmtime/latest/wasmtime/component/struct.ResourceTable.html#method.set_max_capacity Types: Product
    Added Reference Type GitHub, Inc.: https://docs.rs/wasmtime/latest/wasmtime/struct.Store.html#method.set_hostcall_fuel Types: Product
    Added Reference Type GitHub, Inc.: https://docs.rs/wasmtime-wasi/latest/wasmtime_wasi/struct.WasiCtxBuilder.html#method.max_random_size Types: Product
    Added Reference Type GitHub, Inc.: https://docs.wasmtime.dev/security-what-is-considered-a-security-vulnerability.html Types: Product
    Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/issues/11552 Types: Issue Tracking
    Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/pull/12599 Types: Issue Tracking, Third Party Advisory
    Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-852m-cvvp-9p4w Types: Third Party Advisory
  • New CVE Received by [email protected]

    Feb. 24, 2026

    Action Type Old Value New Value
    Added 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.
    Added CVSS V4.0 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
    Added CWE CWE-400
    Added CWE CWE-774
    Added CWE CWE-770
    Added CWE CWE-789
    Added Reference https://docs.rs/wasmtime/latest/wasmtime/component/struct.ResourceTable.html#method.set_max_capacity
    Added Reference https://docs.rs/wasmtime/latest/wasmtime/struct.Store.html#method.set_hostcall_fuel
    Added Reference https://docs.rs/wasmtime-wasi/latest/wasmtime_wasi/struct.WasiCtxBuilder.html#method.max_random_size
    Added Reference https://docs.wasmtime.dev/security-what-is-considered-a-security-vulnerability.html
    Added Reference https://github.com/bytecodealliance/wasmtime/issues/11552
    Added Reference https://github.com/bytecodealliance/wasmtime/pull/12599
    Added Reference https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-852m-cvvp-9p4w
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 6.9
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
VS Confidentiality
VS Integrity
VS Availability
SS Confidentiality
SS Integrity
SS Availability
Base CVSS Score: 6.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact