CVE-2018-12556: n/a vulnerability

CVE-2018-12556: The signature verification routine in install.sh in yarnpkg/website through 2018-06-05 only verifies that t...

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.

UnknownCVSS not scoredNot KEV-listedUpdatedAug 5, 2024, 08:38 UTC (UTC+00:00)

Security readout for executives and security teams

This CVE concerns Yarn's historical install script, which checked that a downloaded release was signed, but did not require the signature to match Yarn's release key. That weak trust check could let a tampered Yarn package appear valid if signed by another key present in the user's local keyring. Exposure is most likely where systems used the affected Yarn install.sh workflow around the vulnerable period. Current exposure cannot be confirmed from the bundle because affected product metadata is listed as n/a and no fixed version is named. Treat as a targeted supply-chain hygiene issue, not an emergency. Prioritize validation in CI, golden images, and older deployment scripts that bootstrap Yarn from legacy installers. Mitigation focus: Check Yarn's official install guidance and release verification documentation.; Avoid legacy install.sh copies dated through 2018-06-05.; Use package manager or installer paths that pin trusted vendor keys..

Prepared: Jun 6, 2026, 20:55 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record

Severity: Unknown
CVSS: Not scored
Known Exploited: No
Published: May 16, 2019, 16:12 UTC (UTC+00:00)

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors

0Timeline events

0ADP providers

5Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

CVE List V5 sourceCVE List V5
https://github.com/yarnpkg/website/commits/masterCVE reference · x_refsource_MISC
[oss-security] 20190430 Spoofing OpenPGP and S/MIME Signatures in Emails (multiple clients)CVE reference · mailing-list, x_refsource_MLIST
https://github.com/RUB-NDS/Johnny-You-Are-FiredCVE reference · x_refsource_MISC
https://github.com/RUB-NDS/Johnny-You-Are-Fired/blob/master/paper/johnny-fired.pdfCVE reference · x_refsource_MISC

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus

n/an/an/aListed

Weakness

CWE details

No CWE listed

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