How severe is CVE-2018-18499?

CVE-2018-18499 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-2018-18499 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-18499?

CVE-2018-18499 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-18499?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-18499 published?

CVE-2018-18499 was published on 2019-02-28 and last updated on 2026-06-17.

CVE-2018-18499

CVE-2018-18499 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

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Affected product: Mozilla Firefox
Published: 2019-02-28
Last modified: 2026-06-17

Description

A same-origin policy violation allowing the theft of cross-origin URL entries when using a meta http-equiv="refresh" on a page to cause a redirection to another site using performance.getEntries(). This is a same-origin policy violation and could allow for data theft. This vulnerability affects Firefox < 62, Firefox ESR < 60.2, and Thunderbird < 60.2.1.

Frequently asked questions

What is CVE-2018-18499?: A same-origin policy violation allowing the theft of cross-origin URL entries when using a meta http-equiv="refresh" on a page to cause a redirection to another site using performance.getEntries(). This is a same-origin policy violation and could allow for data theft. This vulnerability affects Firefox < 62, Firefox ESR < 60.2, and Thunderbird < 60.2.1.
How severe is CVE-2018-18499?: CVE-2018-18499 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-2018-18499 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-18499?: CVE-2018-18499 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-18499?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-18499 published?: CVE-2018-18499 was published on 2019-02-28 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

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