Client crash via nested-worker teardown race
Published Jan 8, 2020 · Updated Aug 5, 2024
Use-after-free in Mozilla Firefox before 71, Firefox ESR before 68.3, and Thunderbird before 68.3 allows remote attackers to crash the client. WorkerPrivate::DisableDebugger omits a wait for nested-worker debugger registration, allowing its queued registration task to write through a WorkerPrivate pointer after the finishing task deletes that object. A crafted page must create and destroy nested workers; Thunderbird disables scripting while reading ordinary mail, limiting exposure to browser-like contexts.
Summary
What happened
Use-after-free in Mozilla Firefox before 71, Firefox ESR before 68.3, and Thunderbird before 68.3 allows remote attackers to crash the client. WorkerPrivate::DisableDebugger omits a wait for nested-worker debugger registration, allowing its queued registration task to write through a WorkerPrivate pointer after the finishing task deletes that object. A crafted page must create and destroy nested workers; Thunderbird disables scripting while reading ordinary mail, limiting exposure to browser-like contexts.
The record
- CVE
- CVE-2019-17008
- Published
- Jan 8, 2020
- Updated
- Aug 5, 2024
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-416, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 8, 2020CVE publishedPublication date reported by the CVE source.
- Aug 5, 2024Record 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=before 71
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- UAF_RegisterDebuggerMainThread_PoC.jsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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