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Fencer Intel
high 7.8

CVE-2019-10773 json

Yarn Improper link resolution before file access (Link Following)

published 6y ago modified last mo. also GHSA-5xf4-f2fq-f69j , EUVD-2020-0291

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

In Yarn before 1.21.1, the package install functionality can be abused to generate arbitrary symlinks on the host filesystem by using specially crafted "bin" keys. Existing files could be overwritten depending on the current user permission set.

Patch / fix

  • npm yarn 1.22.0
  • yarnpkg yarn 1.21.1
  • node-yarnpkg Debian 14, Debian 13, Debian 12 1.21.1-1

debian advisories DEBIAN-CVE-2019-10773

Is CVE-2019-10773 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-10773 updated cvss 7.8

nodejs-yarn: Install functionality can be abused to generate arbitrary symlinks

  • Red Hat Quay v3 quay3/clair-jwt v3.2.1-1
    fixed: vendor fix RHSA-2020:0475

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.52% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/yarnpkg/yarn/issues/7761#issuecomment-565493023 referenced PoC, tagged "exploit" by a source, unverified
  • blog.daniel-ruf.de https://blog.daniel-ruf.de/critical-design-flaw-npm-pnpm-yarn/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
GitHub 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm yarn
<1.22.0
1.22.0

Affected products

  • n/a Yarn

Classification

Weakness
  • CWE-59 Improper Link Resolution Before File Access
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Intel 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.