CVE-2009-1309

CVE-2009-1309 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-16.

Key facts

Description

Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey do not properly implement the Same Origin Policy for (1) XMLHttpRequest, involving a mismatch for a document's principal, and (2) XPCNativeWrapper.toString, involving an incorrect __proto__ scope, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via a crafted document.

Frequently asked questions

What is CVE-2009-1309?
Mozilla Firefox before 3.0.9, Thunderbird, and SeaMonkey do not properly implement the Same Origin Policy for (1) XMLHttpRequest, involving a mismatch for a document's principal, and (2) XPCNativeWrapper.toString, involving an incorrect __proto__ scope, which allows remote attackers to conduct cross-site scripting (XSS) attacks and possibly other attacks via a crafted document.
How severe is CVE-2009-1309?
CVE-2009-1309 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2009-1309 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-1309?
CVE-2009-1309 primarily affects Mozilla Firefox. In total, 102 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-1309?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-1309 published?
CVE-2009-1309 was published on 2009-04-22 and last updated on 2026-06-16.

References

Affected products (102)

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