A curl security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

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Ubuntu Security Notice USN-4665-1
December 09, 2020

curl vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in curl.

Software Description:
- curl: HTTP, HTTPS, and FTP client and client libraries

Details:

Marc Aldorasi discovered that curl incorrectly handled the libcurl
CURLOPT_CONNECT_ONLY option. This could result in data being sent to the
wrong destination, possibly exposing sensitive information. This issue only
affected Ubuntu 20.10. (CVE-2020-8231)

Varnavas Papaioannou discovered that curl incorrectly handled FTP PASV
responses. An attacker could possibly use this issue to trick curl into
connecting to an arbitrary IP address and be used to perform port scanner
and other information gathering. (CVE-2020-8284)

It was discovered that curl incorrectly handled FTP wildcard matchins. A
remote attacker could possibly use this issue to cause curl to consume
resources and crash, resulting in a denial of service. (CVE-2020-8285)

It was discovered that curl incorrectly handled OCSP response verification.
A remote attacker could possibly use this issue to provide a fraudulent
OCSP response. (CVE-2020-8286)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.10:
curl 7.68.0-1ubuntu4.2
libcurl3-gnutls 7.68.0-1ubuntu4.2
libcurl3-nss 7.68.0-1ubuntu4.2
libcurl4 7.68.0-1ubuntu4.2

Ubuntu 20.04 LTS:
curl 7.68.0-1ubuntu2.4
libcurl3-gnutls 7.68.0-1ubuntu2.4
libcurl3-nss 7.68.0-1ubuntu2.4
libcurl4 7.68.0-1ubuntu2.4

Ubuntu 18.04 LTS:
curl 7.58.0-2ubuntu3.12
libcurl3-gnutls 7.58.0-2ubuntu3.12
libcurl3-nss 7.58.0-2ubuntu3.12
libcurl4 7.58.0-2ubuntu3.12

Ubuntu 16.04 LTS:
curl 7.47.0-1ubuntu2.18
libcurl3 7.47.0-1ubuntu2.18
libcurl3-gnutls 7.47.0-1ubuntu2.18
libcurl3-nss 7.47.0-1ubuntu2.18

In general, a standard system update will make all the necessary changes.

References:
  https://usn.ubuntu.com/4665-1
CVE-2020-8231, CVE-2020-8284, CVE-2020-8285, CVE-2020-8286

Package Information:
  https://launchpad.net/ubuntu/+source/curl/7.68.0-1ubuntu4.2
  https://launchpad.net/ubuntu/+source/curl/7.68.0-1ubuntu2.4
  https://launchpad.net/ubuntu/+source/curl/7.58.0-2ubuntu3.12
  https://launchpad.net/ubuntu/+source/curl/7.47.0-1ubuntu2.18