PyPi: Cryptography

CVE-2018-10903

Safety vulnerability ID: 36351

This vulnerability was reviewed by experts

The information on this page was manually curated by our Cybersecurity Intelligence Team.

Created at Jul 30, 2018 Updated at Oct 18, 2024
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Advisory

A flaw was found in python-cryptography versions between >=1.9.0 and <2.3. The finalize_with_tag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalize_with_tag an attacker could craft an invalid payload with a shortened tag (e.g. 1 byte) such that they would have a 1 in 256 chance of passing the MAC check. GCM tag forgeries can cause key leakage. See: CVE-2018-10903.

Affected package

cryptography

Latest version: 43.0.3

cryptography is a package which provides cryptographic recipes and primitives to Python developers.

Affected versions

Fixed versions

Vulnerability changelog

A flaw was found in python-cryptography versions between >=1.9.0 and <2.3. The finalize_with_tag API did not enforce a minimum tag length. If a user did not validate the input length prior to passing it to finalize_with_tag an attacker could craft an invalid payload with a shortened tag (e.g. 1 byte) such that they would have a 1 in 256 chance of passing the MAC check. GCM tag forgeries can cause key leakage.


CONFIRM:https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903: https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903
CONFIRM:https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef: https://github.com/pyca/cryptography/pull/4342/commits/688e0f673bfbf43fa898994326c6877f00ab19ef

Resources

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Severity Details

CVSS Base Score

HIGH 7.5

CVSS v3 Details

HIGH 7.5
Attack Vector (AV)
NETWORK
Attack Complexity (AC)
LOW
Privileges Required (PR)
NONE
User Interaction (UI)
NONE
Scope (S)
UNCHANGED
Confidentiality Impact (C)
HIGH
Integrity Impact (I)
NONE
Availability Availability (A)
NONE

CVSS v2 Details

MEDIUM 5.0
Access Vector (AV)
NETWORK
Access Complexity (AC)
LOW
Authentication (Au)
NONE
Confidentiality Impact (C)
PARTIAL
Integrity Impact (I)
NONE
Availability Impact (A)
NONE