CVE-2022-35954: Delimiter injection vulnerability in @actions/core exportVariable

Severity: medium (CVSS 5.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-08-15 · updated 2026-06-17
Weakness: CWE-77

Description

The GitHub Actions ToolKit provides a set of packages to make creating actions easier. The `core.exportVariable` function uses a well known delimiter that attackers can use to break out of that specific variable and assign values to other arbitrary variables. Workflows that write untrusted values to the `GITHUB_ENV` file may cause the path or other environment variables to be modified without the intention of the workflow or action author. Users should upgrade to `@actions/core v1.9.1`. If you are unable to upgrade the `@actions/core` package, you can modify your action to ensure that any user input does not contain the delimiter `_GitHubActionsFileCommandDelimeter_` before calling `core.exportVariable`.

Affected products

actions toolkit: before 1.9.1 — fixed in 1.9.1

How to fix

Upgrade to a fixed version: actions toolkit 1.9.1. Check the vendor advisory for mitigations.

References

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