CVE-2025-49709Network attack vector

Memory corruption via mismatched canvas surface dimensions

Published Jun 11, 2025 · Updated Jul 27, 2026

Out-of-bounds memory access in Mozilla Firefox before 139.0.4 allows remote attackers to corrupt memory through crafted canvas operations. TexUnpackSurface::TexOrSubImage allocates a conversion buffer from the canvas surface dimensions but passes larger IPDL descriptor dimensions to fTexImage2D, causing reads beyond the buffer. A crafted page must exercise the WebGL texture-upload path; observed outcomes include a GPU-process crash, and Mozilla has not published a demonstrated code-execution result.

CVSS severity9.8
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

Out-of-bounds memory access in Mozilla Firefox before 139.0.4 allows remote attackers to corrupt memory through crafted canvas operations. TexUnpackSurface::TexOrSubImage allocates a conversion buffer from the canvas surface dimensions but passes larger IPDL descriptor dimensions to fTexImage2D, causing reads beyond the buffer. A crafted page must exercise the WebGL texture-upload path; observed outcomes include a GPU-process crash, and Mozilla has not published a demonstrated code-execution result.

The record

CVE
CVE-2025-49709
Published
Jun 11, 2025
Updated
Jul 27, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 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

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

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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