checkout-base-test (npm) · Malicious Code
Affects checkout-base-testSource GCVE Database
Malicious package : remove checkout-base-test and rotate any secrets on hosts that installed it.
Data as of 5 Aug 2026, 15:52 UTC
Malicious package
Published to npm · OSV MAL-2026-12544
What to do
Remove checkout-base-test from every project, lockfile and image that pulls it in. Treat any host that installed it as compromised: rotate the credentials, tokens and keys it could read, from a clean machine.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| npmcheckout-base-test | Affected
| Fixed in– |
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Description
The npm package 'checkout-base-test' version 35.9.3 contains malicious code that executes immediately upon import. It constructs attacker-controlled hostnames to fetch a binary payload, which it writes to temporary directories under disguised filenames mimicking legitimate diagnostic files. The payload is then executed detached from the main process. If the primary HTTPS hosts are unreachable, a DNS-TXT based covert channel is used as a fallback. The package uses evasion techniques such as dynamic string concatenation to hide child process usage and environment variable gating to control telemetry. The package name is deceptive and does not provide legitimate functionality.