What’s Vulnerable › Vulnerabilities

CVE-2019-15608

• Severity: medium (CVSS 5.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-03-15 · updated 2026-06-17
• Weakness: CWE-840

Description

The package integrity validation in yarn < 1.19.0 contains a TOCTOU vulnerability where the hash is computed before writing a package to cache. It's not computed again when reading from the cache. This may lead to a cache pollution attack.

Affected products

• yarn: before 1.19.0 — fixed in 1.19.0

How to fix

Upgrade to a fixed version: yarn 1.19.0. Check the vendor advisory for mitigations.

References

• https://github.com/yarnpkg/yarn/blob/master/CHANGELOG.md#1190
• https://github.com/yarnpkg/yarn/commit/0474b8c66a8ea298f5e4dedc67b2de464297ad1c
• https://hackerone.com/reports/703138
• https://github.com/yarnpkg/yarn/blob/master/CHANGELOG.md#1190
• https://github.com/yarnpkg/yarn/commit/0474b8c66a8ea298f5e4dedc67b2de464297ad1c
• https://hackerone.com/reports/703138

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