CVE-2017-5402: Mozilla Firefox vulnerability

CVE-2017-5402: A use-after-free can occur when events are fired for a "FontFace" object after the object has been already...

A use-after-free can occur when events are fired for a "FontFace" object after the object has been already been destroyed while working with fonts. This results in a potentially exploitable crash. This vulnerability affects Firefox < 52, Firefox ESR < 45.8, Thunderbird < 52, and Thunderbird < 45.8.

UnknownCVSS not scoredNot KEV-listedUpdatedAug 5, 2024, 14:55 UTC (UTC+00:00)

Security readout for executives and security teams

This is an old Mozilla memory-safety issue in font handling. A destroyed FontFace object could still receive events, causing a potentially exploitable crash. Business urgency is mainly for environments still running unsupported Firefox, Firefox ESR, or Thunderbird versions from before the 2017 fixes. Exposure is most likely limited to legacy desktops, servers, or packaged applications using affected Mozilla clients. Modern managed browsers and mail clients should not be exposed if updated past the named fixed versions. Prioritize remediation where old Mozilla clients remain in use, especially on internet-facing or user-operated workstations. For fully updated fleets, this should be a hygiene confirmation rather than an emergency response. Mitigation focus: Upgrade Firefox to version 52 or later.; Upgrade Firefox ESR to version 45.8 or later.; Upgrade Thunderbird to version 52 or 45.8 or later, as applicable..

Prepared: Jun 7, 2026, 06:44 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record

Severity: Unknown
CVSS: Not scored
Known Exploited: No
Published: Jun 11, 2018, 21:00 UTC (UTC+00:00)

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors

0Timeline events

0ADP providers

10Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

CVE List V5 sourceCVE List V5
https://bugzilla.mozilla.org/show_bug.cgi?id=1334876CVE reference · x_refsource_CONFIRM
https://www.mozilla.org/security/advisories/mfsa2017-09/CVE reference · x_refsource_CONFIRM
DSA-3832CVE reference · vendor-advisory, x_refsource_DEBIAN
https://www.mozilla.org/security/advisories/mfsa2017-07/CVE reference · x_refsource_CONFIRM
https://www.mozilla.org/security/advisories/mfsa2017-05/CVE reference · x_refsource_CONFIRM
GLSA-201705-06CVE reference · vendor-advisory, x_refsource_GENTOO
DSA-3805CVE reference · vendor-advisory, x_refsource_DEBIAN
https://www.mozilla.org/security/advisories/mfsa2017-06/CVE reference · x_refsource_CONFIRM
GLSA-201705-07CVE reference · vendor-advisory, x_refsource_GENTOO

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus

MozillaFirefoxunspecifiedListed

MozillaFirefox ESRunspecifiedListed

MozillaThunderbirdunspecified, unspecifiedListed

Weakness

CWE details

No CWE listed

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