#VU35031 Out-of-bounds read in typed_ast - CVE-2019-19275

Vulnerability identifier: #VU35031

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-19275

CWE-ID: CWE-125

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
typed_ast
Other software / Other software solutions

Vendor: Python

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

typed_ast 1.3.0 and 1.3.1 has an ast_for_arguments out-of-bounds read. An attacker with the ability to cause a Python interpreter to parse Python source (but not necessarily execute it) may be able to crash the interpreter process. This could be a concern, for example, in a web-based service that parses (but does not execute) Python code. (This issue also affected certain Python 3.8.0-alpha prereleases.)

Mitigation
Install update from vendor's website.

Vulnerable software versions

typed_ast: 1.3.0 - 1.3.1

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External links
https://bugs.python.org/issue36495
https://github.com/python/cpython/commit/a4d78362397fc3bced6ea80fbc7b5f4827aec55e
https://github.com/python/cpython/commit/dcfcd146f8e6fc5c2fc16a4c192a0c5f5ca8c53c
https://github.com/python/typed_ast/commit/156afcb26c198e162504a57caddfe0acd9ed7dce
https://github.com/python/typed_ast/commit/dc317ac9cff859aa84eeabe03fb5004982545b3b
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LG5H4Q6LFVRX7SFXLBEJMNQFI4T5SCEA/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.