CVE-2026-15718Public exploitNetwork attack vector

Code execution via WebAssembly compiler stack desynchronization

Published Jul 14, 2026 · Updated Jul 14, 2026

Invalid-pointer handling in Mozilla Firefox before 152.0.6 allows remote attackers to execute code via crafted WebAssembly content. BaseCompiler::emitArrayFill() omits sync() before a zero-trip reference array.fill loop, so later code reads an unwritten stack slot as a stale pointer. A victim must process attacker-controlled WebAssembly content; the demonstrated chain gains arbitrary process-memory access and native execution, but browser compromise remains content-sandboxed, and Firefox ESR before 140.13 and Thunderbird before 140.13 share the flaw.

CVSS severity4.3
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid-pointer handling in Mozilla Firefox before 152.0.6 allows remote attackers to execute code via crafted WebAssembly content. BaseCompiler::emitArrayFill() omits sync() before a zero-trip reference array.fill loop, so later code reads an unwritten stack slot as a stale pointer. A victim must process attacker-controlled WebAssembly content; the demonstrated chain gains arbitrary process-memory access and native execution, but browser compromise remains content-sandboxed, and Firefox ESR before 140.13 and Thunderbird before 140.13 share the flaw.

The record

CVE
CVE-2026-15718
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-763, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 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?

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

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-763Release of Invalid Pointer or Reference
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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