CVE-2026-4715Network attack vector

Unspecified impact via uninitialized Canvas2D memory

Published Mar 24, 2026 · Updated Mar 24, 2026

Uninitialized memory use in Canvas2D allows remote attackers to cause unspecified impact via crafted web content in Firefox and Thunderbird. Mozilla has not published the responsible function, allocation, or incorrect read operation beyond identifying the Graphics: Canvas2D component. The flaw is network-reachable without authentication, but no more specific consequence is established; Firefox before 149 and ESR before 140.9, including corresponding Thunderbird branches, are affected.

CVSS severity9.1
Critical
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uninitialized memory use in Canvas2D allows remote attackers to cause unspecified impact via crafted web content in Firefox and Thunderbird. Mozilla has not published the responsible function, allocation, or incorrect read operation beyond identifying the Graphics: Canvas2D component. The flaw is network-reachable without authentication, but no more specific consequence is established; Firefox before 149 and ESR before 140.9, including corresponding Thunderbird branches, are affected.

The record

CVE
CVE-2026-4715
Published
Mar 24, 2026
Updated
Mar 24, 2026
Vendor
Mozilla
Product
Firefox
Classifications
CWE-908
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 24, 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=unspecified <149

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <149
Mozilla · Thunderbirdversion=unspecified <140.9; version=unspecified <149
Mozilla · Firefox ESRversion=unspecified <140.9

Published CVSS scores

9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
9.1CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource

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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