CVE-2018-12556

5.9 mediumEPSS 1.8%

The signature verification routine in install.sh in yarnpkg/website through 2018-06-05 only verifies that the yarn release is signed by any (arbitrary) key in the local keyring of the user, and does not pin the signature to the yarn release key, which allows remote attackers to sign tampered yarn release packages with their own key.

Severity

CVSS 3.0

5.9 medium

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

EPSS: 1.8% chance of exploitation in the next 30 days; higher than 78% of CVEs (scores of 2026-10-31)
CWE: CWE-347
Published: 2019-05-16
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

yarnpkg:website

References

http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html
http://seclists.org/fulldisclosure/2019/Apr/38
https://github.com/RUB-NDS/Johnny-You-Are-Fired
https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf
https://github.com/yarnpkg/website/commits/master

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