Debian Security Advisory

DLA-2773-1 curl -- LTS security update

Date Reported:
30 Sep 2021
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2021-22946, CVE-2021-22947.
More information:

Two issues have been found in curl, a command line tool and an easy-to-use client-side library for transferring data with URL syntax.

  • CVE-2021-22946

    Crafted answers from a server might force clients to not use TLS on connections though TLS was required and expected.

  • CVE-2021-22947

    When using STARTTLS to initiate a TLS connection, the server might send multiple answers before the TLS upgrade and such the client would handle them as being trusted. This could be used by a MITM-attacker to inject fake response data.

    For Debian 9 stretch, these problems have been fixed in version 7.52.1-5+deb9u16.

    We recommend that you upgrade your curl packages.

    For the detailed security status of curl please refer to its security tracker page at:

    Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: