CVE-2018-10903

HIGH
7.5
CVSS Score
Published: July 30, 2018 at 03:00 PM UTC
Updated: June 17, 2026 at 01:34 AM UTC
3 products affected across 3 vendorsUbuntu LinuxOpenStackPython Cryptography

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Severity
HIGH7.5
Exploit prediction
EPSS 3%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

1.9.0 ≤ v < 2.32.3
Affected range stops below 2.3, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMIssue TrackingPatchThird Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10903
Vendor Advisoryx_refsource_UBUNTUThird Party Advisory
https://usn.ubuntu.com/3720-1/

CVSS

7.5HIGHredhat
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-20

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