Vulnerability identifier: #VU15945

Vulnerability risk: Low

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-10903

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
python-cryptography
Universal components / Libraries / Programming Languages & Components

Vendor: Python Cryptographic Authority

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information.

The vulnerability exists due to due to insufficient enforcement of a minimum tag length prior to passing user-supplied input to the finalize_with_tag API. A remote attacker can send a specially crafted request that submits a malicious short tag length, trigger key leakage and access sensitive information.

Mitigation
Update to version 2.3.

Vulnerable software versions

python-cryptography: 1.9 - 2.2.2

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External links
http://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef

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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.