Possible vulnerability in sharp at 'npm install' time if an attacker has control over build environment

[Rajaniraiyn]

There's a possible vulnerability in logic that is run only at npm install time when installing versions of sharp prior to the latest v0.30.5.

This is not part of any runtime code, does not affect Windows users at all, and is unlikely to affect anyone that already cares about the security of their build environment. However, out of an abundance of caution, I've created this advisory.

If an attacker has the ability to set the value of the PKG_CONFIG_PATH environment variable in a build environment then they might be able to use this to inject an arbitrary command at npm install time.

I've used the Common Vulnerability Scoring System (CVSS) calculator to determine the maximum possible impact, which suggests a "medium" score of 5.9, but for most people the real impact will be dealing with the noise from automated security tooling that this advisory will bring.

AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C/CR:X/IR:X/AR:X/MAV:X/MAC:X/MPR:X/MUI:R/MS:X/MC:X/MI:X/MA:X

This problem was fixed in commit a6aeef6 and published as part of sharp v0.30.5.