CVE-2018-12402

CVE-2018-12402 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 6.5. 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-346.

Key facts

Description

The internal WebBrowserPersist code does not use correct origin context for a resource being saved. This manifests when sub-resources are loaded as part of "Save Page As..." functionality. For example, a malicious page could recover a visitor's Windows username and NTLM hash by including resources otherwise unreachable to the malicious page, if they can convince the visitor to save the complete web page. Similarly, SameSite cookies are sent on cross-origin requests when the "Save Page As..." menu item is selected to save a page, which can result in saving the wrong version of resources based on those cookies. This vulnerability affects Firefox < 63.

Frequently asked questions

What is CVE-2018-12402?
The internal WebBrowserPersist code does not use correct origin context for a resource being saved. This manifests when sub-resources are loaded as part of "Save Page As..." functionality. For example, a malicious page could recover a visitor's Windows username and NTLM hash by including resources otherwise unreachable to the malicious page, if they can convince the visitor to save the complete web page. Similarly, SameSite cookies are sent on cross-origin requests when the "Save Page As..." menu item is selected to save a page, which can result in saving the wrong version of resources based on those cookies. This vulnerability affects Firefox < 63.
How severe is CVE-2018-12402?
CVE-2018-12402 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2018-12402 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-12402?
CVE-2018-12402 primarily affects Mozilla Firefox. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-12402?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-12402 published?
CVE-2018-12402 was published on 2019-02-28 and last updated on 2026-06-17.

References

Affected products (5)

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