CVE-2019-9821: Race Condition

Reference Links

• https://bugzilla.mozilla.org/show_bug.cgi?id=1539125
• https://www.mozilla.org/security/advisories/mfsa2019-13/
• https://launchpad.net/bugs/cve/CVE-2019-9821
• https://www.mozilla.org/en-US/security/advisories/mfsa2019-13/
• https://www.mozilla.org/en-US/security/advisories/mfsa2019-13/#CVE-2019-11693
• https://www.mozilla.org/en-US/security/advisories/mfsa2019-13/#CVE-2019-9821
• https://security-tracker.debian.org/tracker/CVE-2019-9821
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9821
• https://nvd.nist.gov/vuln/detail/CVE-2019-9821
• https://ubuntu.com/security/CVE-2019-9821

Parent vulnerabilities

(Appears in the following advisories)

• MFSA2019-13

Peer vulnerabilities

(Found alongside the following vulnerabilities)

• CVE-2019-9815
• CVE-2019-9816
• CVE-2019-9817
• CVE-2019-9818
• CVE-2019-9819
• CVE-2019-9820
• CVE-2019-9821
• CVE-2019-11691
• CVE-2019-11692
• CVE-2019-11693
• CVE-2019-7317
• CVE-2019-11694
• CVE-2019-11695
• CVE-2019-11696
• CVE-2019-11697
• CVE-2019-11698
• CVE-2019-11700
• CVE-2019-11699
• CVE-2019-11701
• CVE-2019-9814
• CVE-2019-9800

Frequently Asked Questions

• What is CVE-2019-9821?

  CVE-2019-9821 is a use-after-free vulnerability that can occur in AssertWorkerThread due to a race condition with shared workers.

• How does CVE-2019-9821 affect Firefox?

  CVE-2019-9821 affects Firefox versions prior to 67.

• What is the severity of CVE-2019-9821?

  CVE-2019-9821 has a severity score of 8.1, which is considered high.

• How can I fix CVE-2019-9821?

  To fix CVE-2019-9821, update Firefox to version 67 or later.

• Where can I find more information about CVE-2019-9821?

  You can find more information about CVE-2019-9821 on the following references: [Bugzilla](https://bugzilla.mozilla.org/show_bug.cgi?id=1539125), [Mozilla Security Advisories](https://www.mozilla.org/en-US/security/advisories/mfsa2019-13/)