CVE-2015-1793

Publication date 9 July 2015

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

The X509_verify_cert function in crypto/x509/x509_vfy.c in OpenSSL 1.0.1n, 1.0.1o, 1.0.2b, and 1.0.2c does not properly process X.509 Basic Constraints cA values during identification of alternative certificate chains, which allows remote attackers to spoof a Certification Authority role and trigger unintended certificate verifications via a valid leaf certificate.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
openssl	15.04 vivid	Not affected
	14.10 utopic	Not affected
	14.04 LTS trusty	Not affected
	12.04 LTS precise	Not affected
openssl098	15.04 vivid	Not affected
	14.10 utopic	Not affected
	14.04 LTS trusty	Not in release
	12.04 LTS precise	Not affected

Notes

mdeslaur

introduced by the following commit in 1.0.2b and 1.0.1n: https://git.openssl.org/?p=openssl.git;a=commit;h=6281abc79623419eae6a64768c478272d5d3a426

Severity score breakdown

Parameter	Value
Base score	6.5 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	Low
Integrity impact	Low
Availability impact	None
Vector	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N