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                             CERT-Renater

                 Note d'Information No. 2020/VULN218
_____________________________________________________________________

DATE                : 21/04/2020

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running OpenSSL versions 1.1.1d, 1.1.1e,
                                              1.1.1f.

=====================================================================
https://www.openssl.org/news/secadv/20200421.txt
_____________________________________________________________________


OpenSSL Security Advisory [21 April 2020]
=========================================

Segmentation fault in SSL_check_chain (CVE-2020-1967)
=====================================================

Severity: High

Server or client applications that call the SSL_check_chain() function
during or after a TLS 1.3 handshake may crash due to a NULL pointer
dereference as a result of incorrect handling of the
"signature_algorithms_cert" TLS extension.
The crash occurs if an invalid or unrecognised signature algorithm is
received from the peer. This could be exploited by a malicious peer in a
Denial of Service attack.

OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue.
This issue did not affect OpenSSL versions prior to 1.1.1d.

Affected OpenSSL 1.1.1 users should upgrade to 1.1.1g

This issue was found by Bernd Edlinger and reported to OpenSSL on 7th
April 2020. It was found using the new static analysis pass being
implemented in GCC, -fanalyzer. Additional analysis was performed by
Matt Caswell and Benjamin Kaduk.

Note
=====

This issue did not affect OpenSSL 1.0.2 however these versions are out
of support and no longer receiving public updates. Extended support is
available for premium support customers:
https://www.openssl.org/support/contracts.html

This issue did not affect OpenSSL 1.1.0 however these versions are out
of support and no longer receiving updates.

Users of these versions should upgrade to OpenSSL 1.1.1.

References
==========

URL for this Security Advisory:
https://www.openssl.org/news/secadv/20200421.txt

Note: the online version of the advisory may be updated with additional
details over time.

For details of OpenSSL severity classifications please see:
https://www.openssl.org/policies/secpolicy.html


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+ CERT-RENATER        | tel : 01-53-94-20-44            +
+ 23/25 Rue Daviel    | fax : 01-53-94-20-41            +
+ 75013 Paris         | email:cert@support.renater.fr   +
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