A deserialization vulnerability exists in the way parso through 0.4.0 handles grammar parsing from the cache. Cache loading relies on pickle and, provided that an evil pickle can be written to a cache grammar file and that its parsing can be triggered, this flaw leads to Arbitrary Code Execution. NOTE: This is disputed because "the cache directory is not under control of the attacker in any common configuration.
https://github.com/davidhalter/parso/issues/75
https://gist.github.com/dhondta/f71ae7e5c4234f8edfd2f12503a5dcc7
Published: 2019-06-06
Updated: 2026-06-17
Base Score: 6
Vector: CVSS2#AV:N/AC:M/Au:S/C:P/I:P/A:P
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: High
Base Score: 9.2
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Severity: Critical
EPSS: 0.00665