A curl security update has been released for Ubuntu Linux 18.04 LTS, 20.04 LTS, and 21.04.

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Ubuntu Security Notice USN-5021-1
July 22, 2021

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

- Ubuntu 21.04
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in curl.

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

Details:

Harry Sintonen and Tomas Hoger discovered that curl incorrectly handled
TELNET connections when the -t option was used on the command line.
Uninitialized data possibly containing sensitive information could be sent
to the remote server, contrary to expectations. (CVE-2021-22898,
CVE-2021-22925)

Harry Sintonen discovered that curl incorrectly reused connections in the
connection pool. This could result in curl reusing the wrong connections.
(CVE-2021-22924)

Update instructions:

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

Ubuntu 21.04:
curl 7.74.0-1ubuntu2.1
libcurl3-gnutls 7.74.0-1ubuntu2.1
libcurl3-nss 7.74.0-1ubuntu2.1
libcurl4 7.74.0-1ubuntu2.1

Ubuntu 20.04 LTS:
curl 7.68.0-1ubuntu2.6
libcurl3-gnutls 7.68.0-1ubuntu2.6
libcurl3-nss 7.68.0-1ubuntu2.6
libcurl4 7.68.0-1ubuntu2.6

Ubuntu 18.04 LTS:
curl 7.58.0-2ubuntu3.14
libcurl3-gnutls 7.58.0-2ubuntu3.14
libcurl3-nss 7.58.0-2ubuntu3.14
libcurl4 7.58.0-2ubuntu3.14

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

References:
  https://ubuntu.com/security/notices/USN-5021-1
CVE-2021-22898, CVE-2021-22924, CVE-2021-22925

Package Information:
  https://launchpad.net/ubuntu/+source/curl/7.74.0-1ubuntu2.1
  https://launchpad.net/ubuntu/+source/curl/7.68.0-1ubuntu2.6
  https://launchpad.net/ubuntu/+source/curl/7.58.0-2ubuntu3.14