How severe is CVE-2017-5403?

CVE-2017-5403 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2017-5403 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-5403?

CVE-2017-5403 primarily affects Mozilla Thunderbird. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-5403?

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-2017-5403 published?

CVE-2017-5403 was published on 2018-06-11 and last updated on 2026-06-17.

CVE-2017-5403

CVE-2017-5403 is a critical-severity vulnerability in Mozilla Thunderbird with a CVSS 3.x base score of 9.8. 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-416.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-416
Affected product: Mozilla Thunderbird
Published: 2018-06-11
Last modified: 2026-06-17

Description

When adding a range to an object in the DOM, it is possible to use "addRange" to add the range to an incorrect root object. This triggers a use-after-free, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 52 and Thunderbird < 52.

Frequently asked questions

What is CVE-2017-5403?: When adding a range to an object in the DOM, it is possible to use "addRange" to add the range to an incorrect root object. This triggers a use-after-free, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 52 and Thunderbird < 52.
How severe is CVE-2017-5403?: CVE-2017-5403 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-5403 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-5403?: CVE-2017-5403 primarily affects Mozilla Thunderbird. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-5403?: 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-2017-5403 published?: CVE-2017-5403 was published on 2018-06-11 and last updated on 2026-06-17.

References

Affected products (2)

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

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