CVE-2015-2733

CVE-2015-2733 is a critical-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

Use-after-free vulnerability in the CanonicalizeXPCOMParticipant function in Mozilla Firefox before 39.0 and Firefox ESR 31.x before 31.8 and 38.x before 38.1 allows remote attackers to execute arbitrary code via vectors involving attachment of an XMLHttpRequest object to a dedicated worker.

Frequently asked questions

What is CVE-2015-2733?
Use-after-free vulnerability in the CanonicalizeXPCOMParticipant function in Mozilla Firefox before 39.0 and Firefox ESR 31.x before 31.8 and 38.x before 38.1 allows remote attackers to execute arbitrary code via vectors involving attachment of an XMLHttpRequest object to a dedicated worker.
How severe is CVE-2015-2733?
CVE-2015-2733 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-2015-2733 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-2733?
CVE-2015-2733 primarily affects Mozilla Firefox. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-2733?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2015-2733 published?
CVE-2015-2733 was published on 2015-07-06 and last updated on 2026-06-17.

References

Affected products (20)

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