CVE-2023-25737Public exploitNetwork attack vector

Undefined behavior via invalid SVG element downcast

Published Jun 2, 2023 · Updated Jan 9, 2025

Invalid downcast in Firefox before 110, Firefox ESR before 102.8, and Thunderbird before 102.8 lets remote attackers trigger pointer misuse. SVGUtils::SetupStrokeGeometry obtains an nsTextNode from frame content and treats it as an SVGElement even though the text-node type does not derive from SVGElement. Rendering attacker-controlled SVG text reaches the unsafe cast; Thunderbird disables scripting while reading mail, so its exposure is limited to browser or browser-like contexts.

CVSS severity8.8
High
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid downcast in Firefox before 110, Firefox ESR before 102.8, and Thunderbird before 102.8 lets remote attackers trigger pointer misuse. SVGUtils::SetupStrokeGeometry obtains an nsTextNode from frame content and treats it as an SVGElement even though the text-node type does not derive from SVGElement. Rendering attacker-controlled SVG text reaches the unsafe cast; Thunderbird disables scripting while reading mail, so its exposure is limited to browser or browser-like contexts.

The record

CVE
CVE-2023-25737
Published
Jun 2, 2023
Updated
Jan 9, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-704, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 9, 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=unspecified <110

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <110
Mozilla · Thunderbirdversion=unspecified <102.8
Mozilla · Firefox ESRversion=unspecified <102.8

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.

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-704Incorrect Type Conversion or Cast
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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