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CVE-2018-5121

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in...

5.3 Medium

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in the addressbar. When used as part of an Internationalized Domain Name (IDN) this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 58.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

1.44%Up 1.3 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 5.3

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in the addressbar. When used as part of an Internationalized Domain Name (IDN) this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 58.

Record
CVE-2018-5121
CVSS 3.0
5.3 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness
CWE-20
Updated
2026-11-02
CVE List No score

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in the addressbar. When used as part of an Internationalized Domain Name (IDN) this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 58.

Record
CVE-2018-5121
Updated
2026-11-02
EUVDEUVD-2018-16907 No score

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in the addressbar. When used as part of an Internationalized Domain Name (IDN) this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 58.

Record
EUVD-2018-16907
Updated
2026-11-03
GitHub AdvisoriesGHSA-jcrc-r34f-5gqm 5.3

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in...

Low descenders on some Tibetan characters in several fonts on OS X are clipped when rendered in the addressbar. When used as part of an Internationalized Domain Name (IDN) this can be used for domain name spoofing attacks. Note: This attack only affects OS X operating systems. Other operating systems are unaffected. This vulnerability affects Firefox < 58.

Record
GHSA-jcrc-r34f-5gqm
CVSS 3.0
5.3 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness
CWE-20
Updated
2026-11-02
OSVopenSUSE-SU-2024:10600-1 No score

MozillaFirefox-92.0-1.2 on GA media

These are all security issues fixed in the MozillaFirefox-92.0-1.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:10600-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:14572-1 No score

firefox-esr-128.5.1-1.1 on GA media

These are all security issues fixed in the firefox-esr-128.5.1-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:14572-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
MozillaFirefox
openSUSE:Tumbleweed
From an advisory covering 661 CVEs
before 92.0-1.2
92.0-1.2
firefox-esr
openSUSE:Tumbleweed
From an advisory covering 1860 CVEs
before 128.5.1-1.1
128.5.1-1.1

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-5121 is a medium vulnerability (CVSS 5.3) in Mozilla Firefox, published June 11, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.44%, the 73rd percentile. No source names a fixed version.

References

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