CVE-2020-36242

Published: 07 February 2021

In the cryptography package before 3.3.2 for Python, certain sequences of update calls to symmetrically encrypt multi-GB values could result in an integer overflow and buffer overflow, as demonstrated by the Fernet class.

Priority

Medium

CVSS 3 base score: 9.1

Status

Package Release Status
python-cryptography
Launchpad, Ubuntu, Debian
Upstream
Released (3.3.2)
Ubuntu 21.04 (Hirsute Hippo) Pending
(3.3.2-1)
Ubuntu 20.10 (Groovy Gorilla) Not vulnerable
(3.0-1ubuntu0.1)
Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable
(2.8-3ubuntu0.1)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(2.1.4-1ubuntu1.4)
Ubuntu 16.04 LTS (Xenial Xerus) Not vulnerable
(1.2.3-1ubuntu0.3)
Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

Patches:
Upstream: https://github.com/pyca/cryptography/commit/82b6ce28389f0a317bc55ba2091a74b346db7cae

Notes

AuthorNote
mdeslaur
Versions in groovy and earlier don't support chunking in
update_into. Attempting reproducer on groovy and focal errors
out with:
OverflowError: integer 4294967296 does not fit '32-bit int'
which seems to indicate there is a size check being performed
and they aren't vulnerable to this issue.

References

Bugs