CVE-2018-0739: Constructed ASN.1 types with a recursive definition could exceed the stack
Constructed ASN.1 types with a recursive definition (such as can be found in PKCS7) could eventually exceed the stack given malicious input with excessive recursion. This could result in a Denial Of Service attack. There are no such structures used within SSL/TLS that come from untrusted sources so this is considered safe. Fixed in OpenSSL 1.1.0h (Affected 1.1.0-1.1.0g). Fixed in OpenSSL 1.0.2o (Affected 1.0.2b-1.0.2n).
Other sources
OpenSSL is vulnerable to a denial of service. By sending specially crafted ASN.1 data with a recursive definition, a remote attacker could exploit this vulnerability to consume excessive stack memory.
— IBM
OpenSSL versions 1.0.2 and 1.1.0 have a vulnerability in the handling of recursive ASN.1 structures. Constructed ASN.1 types with a recursive definition (such as can be found in PKCS7) could eventually exceed the stack given malicious input with excessive recursion. This could result in a Denial Of Service attack. There are no such structures used within SSL/TLS that come from untrusted sources so this is considered safe.
External References:
https://www.openssl.org/news/secadv/20180327.txt
Upstream Patches:
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=2ac4c6f7b2b2af20c0e2b0ba05367e454cd11b33 https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9310d45087ae546e27e61ddf8f6367f29848220d
— Red Hat
Affected Software
Remediation
Event History
Frequently Asked Questions
What is CVE-2018-0739?
CVE-2018-0739 is a vulnerability in OpenSSL that could result in a Denial of Service attack.
What is the severity of CVE-2018-0739?
CVE-2018-0739 has a severity score of 6.5 (Medium).
Which software versions are affected by CVE-2018-0739?
The OpenSSL versions 1.1.0 and 1.0.2 are affected by CVE-2018-0739.
How can I fix CVE-2018-0739?
To fix CVE-2018-0739, you should update OpenSSL to version 1.0.2 or 1.1.0, as recommended by the vendor.
Where can I find more information about CVE-2018-0739?
You can find more information about CVE-2018-0739 on the OpenSSL website and the provided references.