CJK codecs tests call eval() on content retrieved via HTTP¶
By default, the tests are not run with network resources enabled and so the Python test suite is safe.
But if the Python test suite is run explicitly with the “network” resource
enabled (-u network or -u all command line option), the CJK codecs
tests of the Python test suite run eval() on content received via HTTP
from pythontest.net.
If an attacker can compromise the pythontest.net server, they gain
arbitrary code execution on all buildbots.
If an attacker has control over the network connection of a machine running the Python test suite, they gain arbitrary code execution there.
make testall, make testuniversal and make buildbottest commands
are impacted (pass -u all option to the test suite).
The CI of the Python project is impacted (buildbot, Travis CI, GitHub Action, Azure Pipelines).
With the fix, content is still retrieved via HTTP, but the unsafe eval() function is no longer used.
Dates:
- Disclosure date: 2020-10-05 (Python issue bpo-41944 reported)
- Reported at: 2020-10-05 (email sent to the PSRT list)
- Reported by: Florian Bruhin
Fixed In¶
- Python 3.6.13 (2021-02-16) fixed by commit e912e94 (branch 3.6) (2020-10-20)
- Python 3.7.10 (2021-02-16) fixed by commit 43e5231 (branch 3.7) (2020-10-20)
- Python 3.8.7 (2020-12-21) fixed by commit 6c6c256 (branch 3.8) (2020-10-06)
- Python 3.9.1 (2020-12-07) fixed by commit b664a1d (branch 3.9) (2020-10-06)
- Python 3.10.0 (2021-10-04) fixed by commit 2ef5caa (branch 3.10) (2020-10-06)
Python issue¶
[security][CVE-2020-27619] Python testsuite calls eval() on content received via HTTP.
- Python issue: bpo-41944
- Creation date: 2020-10-05
- Reporter: Serhiy Storchaka
CVE-2020-27619¶
In Python 3 through 3.9.0, the Lib/test/multibytecodec_support.py CJK codec tests call eval() on content retrieved via HTTP.
- CVE ID: CVE-2020-27619
- Published: 2020-10-22
- CVSS Score: 7.5
Timeline¶
Timeline using the disclosure date 2020-10-05 as reference:
- 2020-10-05: Reported (email sent to the PSRT list)
- 2020-10-05: Python issue bpo-41944 reported by Serhiy Storchaka
- 2020-10-06 (+1 days): commit 2ef5caa (branch 3.10)
- 2020-10-06 (+1 days): commit 6c6c256 (branch 3.8)
- 2020-10-06 (+1 days): commit b664a1d (branch 3.9)
- 2020-10-20 (+15 days): commit 43e5231 (branch 3.7)
- 2020-10-20 (+15 days): commit e912e94 (branch 3.6)
- 2020-10-22 (+17 days): CVE-2020-27619 published
- 2020-12-07 (+63 days): Python 3.9.1 released
- 2020-12-21 (+77 days): Python 3.8.7 released
- 2021-02-16 (+134 days): Python 3.6.13 released
- 2021-02-16 (+134 days): Python 3.7.10 released
- 2021-10-04: Python 3.10.0 released