CVE-2025-1011Public exploitNetwork attack vector

Crash via hoisted WebAssembly reference load

Published Feb 4, 2025 · Updated Apr 13, 2026

WebAssembly code-generation flaw in Mozilla Firefox and Thunderbird before 135 allows remote attackers to trigger a crash with crafted content. The optimizing compiler marks MWasmI31RefGet as movable, so loop-invariant code motion hoists i31.get before its ref.cast and null-trap guards. Exploitation requires processing attacker-controlled WebAssembly; Firefox ESR before 128.7 is affected, and Mozilla identifies code execution as an additional possible consequence.

CVSS severity8.8
High
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

WebAssembly code-generation flaw in Mozilla Firefox and Thunderbird before 135 allows remote attackers to trigger a crash with crafted content. The optimizing compiler marks MWasmI31RefGet as movable, so loop-invariant code motion hoists i31.get before its ref.cast and null-trap guards. Exploitation requires processing attacker-controlled WebAssembly; Firefox ESR before 128.7 is affected, and Mozilla identifies code execution as an additional possible consequence.

The record

CVE
CVE-2025-1011
Published
Feb 4, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-94, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8INCIBE-CERTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
5.3Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/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.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo