When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.
https://www.oracle.com/security-alerts/cpuoct2021.html
https://www.debian.org/security/2022/dsa-5197
https://support.apple.com/kb/HT213183
https://security.netapp.com/advisory/ntap-20211029-0003/
https://security.gentoo.org/glsa/202212-01
https://hackerone.com/reports/1269242
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf