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Vulnerabilities

Vulnerability · CVE-2026-58592

Ladybird - Web-Reachable Code Execution via Dangling FunctionType Reference in WebAssembly ESM Integration

Published Jul 1, 2026 · catalog updated Sep 11, 2026 · LadybirdBrowser Ladybird

Last checked Nov 1, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-58592. EPSS is 0.55%. Act only if a listed version of LadybirdBrowser Ladybird is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High8.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.55%
Remediation
Advisory link
Affected products
vendor LadybirdBrowser Ladybird

Ladybird before commit 2f9dc7e contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop iteration ends the FunctionType is destroyed, leaving the callback with a dangling reference (the normal instantiate path uses a long-lived reference and is not affected). Stale result-type data lets the host callback return an empty result vector for a statically non-empty result, so the destination register retains an attacker-influenced value that is then consumed by the WASM-GC array.set handler, which bit-casts the reference low bits to an ArrayInstance pointer after only a null check, yielding an arbitrary write. A web page can chain this into code execution in the WebContent process. Verified reachable from HTML content without any instrumentation or source modification.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor LadybirdBrowser Ladybirdversion unspecified

How to fix CVE-2026-58592

  • No stored fix

    No vendor fix text is stored. Use the linked advisory before you change production.

  • Version check

    No version range is stored, so an installed version cannot be checked on this page.

  • Advisory

    Open the cve_org record and follow its fix.

  • Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-58592. EPSS is 0.55%. Act only if a listed version of LadybirdBrowser Ladybird is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-787: Out-of-bounds Write; CWE-825; CWE-843: Access of Resource Using Incompatible Type (Type Confusion). EPSS 0.55%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 11, 2026 · CVE.org

    Updated

    Ladybird before commit 2f9dc7e contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop ite

  2. Oct 25, 2026 · Tenable CVE Database

    Detected

    Ladybird before commit 2f9dc7e contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop ite

Sources

  • CVE.orgVulnerability recordCVE-2026-58592

    Ladybird before commit 2f9dc7e contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by re

    cve.org
  • Tenable CVE DatabaseVulnerability recordCVE-2026-58592

    Ladybird before commit 2f9dc7e contains a dangling-reference memory-safety flaw in its WebAssembly ESM-integration module loader. When a JavaScript function is imported into a WebAssembly module via the ESM path, WebAssemblyModule.cpp passes a stack-local Wasm::FunctionType by reference to create_host_function, whose host callback captures and later reads that reference; once the ESM link-loop ite

    tenable.com

References

Freshness

Last verified in this catalog Nov 1, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 26, 2026
  • Tenable CVE DatabaseOct 26, 2026