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OpenAdvisories
Medium · 5.3 CVE-2021-22897 EUVD-2021-10029GHSA-frcg-47mh-pj2g

curl 7.61.0 through 7.76.1 suffers from exposure of data element to wrong session due to a mistake in the code for CURLOPT_SSL_CIPHER_LIST …

Published Jun 11, 2021 · Updated Oct 14, 2026 · Assigned by hackerone

Package: curl Ecosystem: Azure Linux

Description

curl 7.61.0 through 7.76.1 suffers from exposure of data element to wrong session due to a mistake in the code for CURLOPT_SSL_CIPHER_LIST when libcurl is built to use the Schannel TLS library. The selected cipher set was stored in a single "static" variable in the library, which has the surprising side-effect that if an application sets up multiple concurrent transfers, the last one that sets the ciphers will accidentally control the set used by all transfers. In a worst-case scenario, this weakens transport security significantly.

Affected products

VendorProductAffectedFixed
— https://github.com/curl/curl 7.61.0 through 7.76.1 —

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.

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 2 (CBL-Mariner) curl 7.76.0-5 —

Advisories 10

References