CVE-2025-47154Public exploitNetwork attack vector

Remote code execution via constructor reentrancy

Published May 1, 2025 · Updated May 1, 2025

Use-after-free in LibJS in Ladybird before f5a6704 allows remote attackers to execute arbitrary code via crafted JavaScript. ECMAScriptFunctionObject::internal_construct retains arguments_list into the VM argument buffer while a proxied new_target getter runs reentrant JavaScript that reallocates that buffer. The crafted script must execute in LibJS; subsequent argument access dereferences the stale pointer in the renderer context.

CVSS severity9.0
Critical
EPSS probability0.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in LibJS in Ladybird before f5a6704 allows remote attackers to execute arbitrary code via crafted JavaScript. ECMAScriptFunctionObject::internal_construct retains arguments_list into the VM argument buffer while a proxied new_target getter runs reentrant JavaScript that reallocates that buffer. The crafted script must execute in LibJS; subsequent argument access dereferences the stale pointer in the renderer context.

The record

CVE
CVE-2025-47154
Published
May 1, 2025
Updated
May 1, 2025
Vendor
Ladybird Browser Initiative
Product
Ladybird
Classifications
CWE-820, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 1, 2025CVE publishedPublication date reported by the CVE source.
  2. May 1, 2025Record 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=0 <f5a670421954fc7130c3685b713c621b29516669

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ladybird Browser Initiative · Ladybirdversion=0 <f5a670421954fc7130c3685b713c621b29516669

Published CVSS scores

9.0MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-820Missing Synchronization
T1203Exploitation for Client Execution

Public exploit references

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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