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Fencer Vulns
low 3.5

CVE-2020-15228 json

Environment Variable Injection in GitHub Actions

published 2020-10-01 6 y ago modified 2026-06-17 4 mo ago also GHSA-mfwh-5m23-j46w , EUVD-2020-1433

cvss
3.5
version 3.1, CNA
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 the `@actions/core` npm module before version 1.2.6,`addPath` and `exportVariable` functions communicate with the Actions Runner over stdout by generating a string in a specific format. Workflows that log untrusted data to stdout may invoke these commands, resulting in the path or environment variables being modified without the intention of the workflow or action author. The runner will release an update that disables the `set-env` and `add-path` workflow commands in the near future. For now, users should upgrade to `@actions/core v1.2.6` or later, and replace any instance of the `set-env` or `add-path` commands in their workflows with the new Environment File Syntax. Workflows and actions using the old commands or older versions of the toolkit will start to warn, then error out during workflow execution.

Patch / fix

  • npm @actions/core 1.2.6
  • toolkit_project toolkit 1.2.6

Exploit prediction

1.49% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • packetstormsecurity.com http://packetstormsecurity.com/files/159794/GitHub-Widespread-Injection.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N
NVD 3.1 5.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:P/A:N
GitHub 3.1 3.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
npm @actions/core
<1.2.6
1.2.6

Affected products

  • actions toolkit

Classification

Weakness
  • CWE-20 Improper Input Validation
  • CWE-77 Improper Neutralization of Special Elements used in a Command

References

Sources

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.