CVE-2018-12556 json
The signature verification routine in install.sh in yarnpkg/website through 2018-06-05 only verifies that the yarn release is signed by any…
published 2019-05-16 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-4516
- cvss
- 5.9
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.8%
- EPSS 1.8% chance of exploitation in 30 days, percentile 78%
- public exploits
- 0
- none known
Summary
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.
Exploit prediction
1.77% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 5.9 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
github.com
/yarnpkg/website/commits/master
third-party-advisory
-
seclists.org
/fulldisclosure/2019/Apr/38
mailing-list, third-party-advisory
-
packetstormsecurity.com
/files/152703/Johnny-You-Are-Fired.html
third-party-advisory, vdb-entry
-
openwall.com
/lists/oss-security/2019/04/30/4
mailing-list, third-party-advisory
-
github.com
/RUB-NDS/Johnny-You-Are-Fired
third-party-advisory
-
github.com
/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdf
third-party-advisory
Sources
- CVE List CVE-2018-12556
- NVD CVE-2018-12556
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.