CVE-2025-3029Public exploitNetwork attack vector

Origin spoofing via unencoded Unicode variation selectors

Published Apr 1, 2025 · Updated Apr 13, 2026

URL bar spoofing in Mozilla Firefox and Thunderbird allows remote attackers to conceal a page's true origin using a crafted URL. The address-bar formatting code fails to encode supplementary-plane variation selectors, so U+E012A combined with spaces and an RTL domain can push the genuine origin out of view. A user must open the crafted URL; the displayed query text can then impersonate another HTTPS address, enabling credential-targeting deception without changing the loaded origin.

CVSS severity7.3
High
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

URL bar spoofing in Mozilla Firefox and Thunderbird allows remote attackers to conceal a page's true origin using a crafted URL. The address-bar formatting code fails to encode supplementary-plane variation selectors, so U+E012A combined with spaces and an RTL domain can push the genuine origin out of view. A user must open the crafted URL; the displayed query text can then impersonate another HTTPS address, enabling credential-targeting deception without changing the loaded origin.

The record

CVE
CVE-2025-3029
Published
Apr 1, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-290, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 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

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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

7.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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-290Authentication Bypass by Spoofing
T1036Masquerading

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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