Cross-origin redirect disclosure via mismatched performance timings
Published Dec 22, 2022 · Updated Apr 15, 2025
Information disclosure in Firefox before 100 allows remote attackers to detect cross-origin redirects through the Performance API. The PerformanceResourceTiming implementation exposes a delta between fetchStart and startTime after a failed Timing-Allow-Origin check instead of assigning both values the request start time. Visiting attacker-controlled web content is required, and the observable timing difference reveals whether a requested cross-origin URL redirected.
Summary
What happened
Information disclosure in Firefox before 100 allows remote attackers to detect cross-origin redirects through the Performance API. The PerformanceResourceTiming implementation exposes a delta between fetchStart and startTime after a failed Timing-Allow-Origin check instead of assigning both values the request start time. Visiting attacker-controlled web content is required, and the observable timing difference reveals whether a requested cross-origin URL redirected.
The record
- CVE
- CVE-2022-29915
- Published
- Dec 22, 2022
- Updated
- Apr 15, 2025
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-346, T1189
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 22, 2022CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=unspecified <100
What conditions does exploitation require?
What is affected?
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.
Public exploit references
- Bug 1751678 redirect-timing proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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