Bug 1941965 (CVE-2021-22890) - CVE-2021-22890 curl: TLS 1.3 session ticket mix-up with HTTPS proxy host
Summary: CVE-2021-22890 curl: TLS 1.3 session ticket mix-up with HTTPS proxy host
Alias: CVE-2021-22890
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1945059 1945064
Blocks: 1941974
TreeView+ depends on / blocked
Reported: 2021-03-23 10:07 UTC by Marian Rehak
Modified: 2022-04-17 21:15 UTC (History)
33 users (show)

Fixed In Version: curl 7.76.0
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the way libcurl handled TLS 1.3 session tickets. A malicious HTTPS proxy could possibly use this flaw to make libcurl resume a TLS session it previously had with the proxy while intending to resume a TLS session with a target server, making it possible for the proxy to perform a man-in-the-middle attack.
Clone Of:
Last Closed: 2021-06-17 15:04:48 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:2471 0 None None None 2021-06-17 11:36:03 UTC
Red Hat Product Errata RHSA-2021:2472 0 None None None 2021-06-17 11:46:05 UTC

Description Marian Rehak 2021-03-23 10:07:15 UTC
When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed.

Upstream Advisory:


Comment 3 Tomas Hoger 2021-03-29 21:10:27 UTC
According to upstream advisory, this issue was introduced via the following commit first included in curl version 7.63.0:


The curl packages in Red Hat Enterprise Linux 8 and earlier, and the httpd24-curl packages in Red Hat Software Collections are based on older curl versions which do not include the mentioned change and are therefore not affected by this issue.

Upstream advisory also notes that this only affects curl versions using OpenSSL as its TLS/SSL backend.  The issue can occur when using TLS 1.3 and HTTPS proxy (and not the traditional HTTP proxy).

Comment 4 Tomas Hoger 2021-03-29 21:12:38 UTC

Name: the Curl project
Upstream: Mingtao Yang (Facebook)

Comment 6 Tomas Hoger 2021-03-31 10:04:16 UTC
External References:


Comment 7 Tomas Hoger 2021-03-31 10:04:56 UTC
Created curl tracking bugs for this issue:

Affects: fedora-all [bug 1945059]

Comment 10 errata-xmlrpc 2021-06-17 11:35:56 UTC
This issue has been addressed in the following products:

  JBoss Core Services Apache HTTP Server 2.4.37 SP8

Via RHSA-2021:2471 https://access.redhat.com/errata/RHSA-2021:2471

Comment 11 errata-xmlrpc 2021-06-17 11:45:56 UTC
This issue has been addressed in the following products:

  JBoss Core Services on RHEL 7
  JBoss Core Services for RHEL 8

Via RHSA-2021:2472 https://access.redhat.com/errata/RHSA-2021:2472

Comment 12 Product Security DevOps Team 2021-06-17 15:04:48 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


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