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OpenAdvisories
High · 7.5 CVE-2021-22926 EUVD-2021-10055GHSA-5xph-62q2-pxff

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` opti…

Published Aug 5, 2021 · Updated Oct 14, 2026 · Assigned by hackerone

Package: curl Package: curl Ecosystem: Alpine Ecosystem: Azure Linux

Description

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

Affected products

VendorProductAffectedFixed
— https://github.com/curl/curl curll 7.33.0 to and include 7.77.0 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Alpine

Security tracker ↗
ReleasePackageFixed inAdvisory
Alpine v3.11 curl 7.67.0-r5 —

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 2 (CBL-Mariner) curl 7.82.0-1 —

Advisories 12

References