CVE-2022-29912Network attack vector

Cross-site cookie leakage via reader mode

Published Dec 22, 2022 · Updated Apr 15, 2025

SameSite cookie policy bypass in Mozilla Firefox before 100 allows remote attackers to cause protected cookies to accompany reader-mode requests. Reader mode failed to omit cookies marked with a SameSite attribute when navigating or redirecting article content, sending them in contexts where site isolation expected omission. Exploitation requires a victim to open attacker-influenced content in reader mode; the defect can disclose or alter cookie-authenticated web state, while Thunderbird disables scripting when reading mail.

CVSS severity6.1
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SameSite cookie policy bypass in Mozilla Firefox before 100 allows remote attackers to cause protected cookies to accompany reader-mode requests. Reader mode failed to omit cookies marked with a SameSite attribute when navigating or redirecting article content, sending them in contexts where site isolation expected omission. Exploitation requires a victim to open attacker-influenced content in reader mode; the defect can disclose or alter cookie-authenticated web state, while Thunderbird disables scripting when reading mail.

The record

CVE
CVE-2022-29912
Published
Dec 22, 2022
Updated
Apr 15, 2025
Vendor
Mozilla
Product
Firefox
Classifications
Unavailable
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 <100

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <100
Mozilla · Thunderbirdversion=unspecified <91.9
Mozilla · Firefox ESRversion=unspecified <91.9

Published CVSS scores

6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 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

No sourced classifications are available.

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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