FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

ksh93 -- certain environment variables interpreted as arithmetic expressions on startup, leading to code injection

Affected packages
ksh93 < 2020.0.1_1,1
ksh93-devel < 2020.02.07


VuXML ID 8b20d716-49df-11ea-9f7b-206a8a720317
Discovery 2019-10-01
Entry 2020-02-07

Upstream ksh93 maintainer Siteshwar Vashisht reports:

A flaw was found in the way ksh evaluates certain environment variables. An attacker could use this flaw to override or bypass environment restrictions to execute shell commands. Services and applications that allow remote unauthenticated attackers to provide one of those environment variables could allow them to exploit this issue remotely.