CVE-2018-5121

5.3 MEDIUM 1% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 1.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2018-06-11 21:29 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 01:59 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.4% in the next 30 days (EPSS).
Severity: 5.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2018-06-11 21:29 UTC
Last modified: 2026-06-17 01:59 UTC
Exploit probability: 1.4% · EPSS, next 30 days
Weakness: CWE-20 · Improper input validation
Record status: Modified

Affected

Mozilla Firefox ≤ 57.0.4

Attack profile CVSS 3.0 · 5.3

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Raw vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2018-5121.md and follow it. Check whether this project is affected by CVE-2018-5121. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record