CVE-2022-34477Public exploitNetwork attack vector

Cross-origin state disclosure via distinct MediaError messages

Published Dec 22, 2022 · Updated Apr 15, 2025

Observable discrepancy in Mozilla Firefox before 102 allows remote attackers to infer cross-origin resource state through MediaError messages. The media error path used a same-site third-party test instead of a same-origin check, exposing distinct request-failure and HTTP-status messages to scripts. A malicious same-site origin can compare those messages to detect resource availability or login state; the disclosure does not grant response-body access.

CVSS severity7.5
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable discrepancy in Mozilla Firefox before 102 allows remote attackers to infer cross-origin resource state through MediaError messages. The media error path used a same-site third-party test instead of a same-origin check, exposing distinct request-failure and HTTP-status messages to scripts. A malicious same-site origin can compare those messages to detect resource availability or login state; the disclosure does not grant response-body access.

The record

CVE
CVE-2022-34477
Published
Dec 22, 2022
Updated
Apr 15, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 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 <102

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <102

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-203Observable Discrepancy

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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