CVE-2026-54786Network attack vector

Host resource exhaustion via fd_renumber descriptor leak

Published Jul 1, 2026 · Updated Jul 1, 2026

Resource exhaustion in Bytecode Alliance Wasmtime allows guest OS users to exhaust host file descriptors through repeated WASIp1 fd_renumber calls. The native WASIp1 implementation updates its descriptor table without closing the destination in the host table, leaking resources until the Store is destroyed. Exploitation requires a core WebAssembly module with fd_renumber exposed and permission to acquire file descriptors; runtimes that deny file access are unaffected.

CVSS severity2.3
Low
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Bytecode Alliance Wasmtime allows guest OS users to exhaust host file descriptors through repeated WASIp1 fd_renumber calls. The native WASIp1 implementation updates its descriptor table without closing the destination in the host table, leaking resources until the Store is destroyed. Exploitation requires a core WebAssembly module with fd_renumber exposed and permission to acquire file descriptors; runtimes that deny file access are unaffected.

The record

CVE
CVE-2026-54786
Published
Jul 1, 2026
Updated
Jul 1, 2026
Vendor
Bytecode Alliance
Product
Wasmtime
Classifications
CWE-400, CWE-772, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 24.0.10
  2. Affected versionversion=>= 25.0.0, < 36.0.11
  3. Affected versionversion=>= 37.0.0, < 44.0.3
  4. Affected versionversion=>= 45.0.0, < 45.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Bytecode Alliance · Wasmtimeversion=< 24.0.10; version=>= 25.0.0, < 36.0.11; version=>= 37.0.0, < 44.0.3; version=>= 45.0.0, < 45.0.2

Published CVSS scores

5.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L
2.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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