CVE-2018-12556

low-risk
Published 2019-05-16

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.

Do I need to act?

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0.34% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.9/10 Medium
NETWORK / HIGH complexity

Affected Products (1)

Website

Affected Vendors

Yarnpkg

References (12)

Third Party Advisory http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html
Mailing List http://seclists.org/fulldisclosure/2019/Apr/38
Third Party Advisory https://github.com/RUB-NDS/Johnny-You-Are-Fired
Third Party Advisory https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.p...
Third Party Advisory https://github.com/yarnpkg/website/commits/master
Mailing List https://www.openwall.com/lists/oss-security/2019/04/30/4
Third Party Advisory http://packetstormsecurity.com/files/152703/Johnny-You-Are-Fired.html
Mailing List http://seclists.org/fulldisclosure/2019/Apr/38
Third Party Advisory https://github.com/RUB-NDS/Johnny-You-Are-Fired
Third Party Advisory https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.p...
Third Party Advisory https://github.com/yarnpkg/website/commits/master
Mailing List https://www.openwall.com/lists/oss-security/2019/04/30/4
24
/ 100
low-risk
Severity 18/34 · Moderate
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal