How severe is CVE-2018-5114?

CVE-2018-5114 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2018-5114 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-5114?

CVE-2018-5114 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-5114?

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

When was CVE-2018-5114 published?

CVE-2018-5114 was published on 2018-06-11 and last updated on 2026-06-17.

CVE-2018-5114

CVE-2018-5114 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 5.3. 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-200.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Mozilla Firefox
Published: 2018-06-11
Last modified: 2026-06-17

Description

If an existing cookie is changed to be "HttpOnly" while a document is open, the original value remains accessible through script until that document is closed. Network requests correctly use the changed HttpOnly cookie. This vulnerability affects Firefox < 58.

Frequently asked questions

What is CVE-2018-5114?: If an existing cookie is changed to be "HttpOnly" while a document is open, the original value remains accessible through script until that document is closed. Network requests correctly use the changed HttpOnly cookie. This vulnerability affects Firefox < 58.
How severe is CVE-2018-5114?: CVE-2018-5114 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2018-5114 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-5114?: CVE-2018-5114 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-5114?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-5114 published?: CVE-2018-5114 was published on 2018-06-11 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:17.10:*:*:*:*:*:*:*

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