Bug 1970902 (CVE-2021-22925) - CVE-2021-22925 curl: Incorrect fix for CVE-2021-22898 TELNET stack contents disclosure
Summary: CVE-2021-22925 curl: Incorrect fix for CVE-2021-22898 TELNET stack contents d...
Alias: CVE-2021-22925
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1970934 1970935 1970936 1984328 1984329
Blocks: 1970904
TreeView+ depends on / blocked
Reported: 2021-06-11 12:33 UTC by Tomas Hoger
Modified: 2023-06-06 15:08 UTC (History)
36 users (show)

Fixed In Version: curl 7.78.0
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the way curl handled telnet protocol option for sending environment variables, which could lead to sending of uninitialized data from a stack-based buffer to the server. This issue leads to potentially revealing sensitive internal information to the server using a clear-text network protocol.
Clone Of:
Last Closed: 2021-11-09 23:22:48 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:4511 0 None None None 2021-11-09 19:02:48 UTC

Description Tomas Hoger 2021-06-11 12:33:06 UTC
CVE-2021-22898: TELNET stack contents disclosure (see bug 1964887) issue was recently reported for curl and it was addressed in curl 7.77.0:


However, the fix applied is not correct and does not completely address the issue.  It helps in cases when long environment variable name is used ('a'*256 + ',b'), but not when the name is short and only the value is long ('a,' + 'b'*256, which is the example mentioned in the curl project advisory).

Long variable values still trigger memory disclosure as described in the original report.

This issue was reported upstream via:


Comment 5 Marian Rehak 2021-07-21 09:15:32 UTC
Created curl tracking bugs for this issue:

Affects: fedora-all [bug 1984328]

Created mingw-curl tracking bugs for this issue:

Affects: fedora-all [bug 1984329]

Comment 8 errata-xmlrpc 2021-11-09 19:02:45 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:4511 https://access.redhat.com/errata/RHSA-2021:4511

Comment 9 Product Security DevOps Team 2021-11-09 23:22:43 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 10 Tomas Hoger 2022-05-26 11:34:27 UTC
Upstream advisory:

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