CVE-2021-22901: exploitation status and patch state
CVE-2021-22901 · CVSS 8.1 HIGH · EPSS 60%
curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session ticket arrives over a connection. A malicious server can use this in rare unfortunate circumstances to potentially reach remote code execution in the client. When libcurl at run-time sets up support for TLS 1.3 session tickets on a connection using OpenSSL, it stores pointers to the transfer in-memory object for later retrieval when a session ticket arrives. If the connection is used by multiple transfers (like with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection) that first transfer object might be freed before the new session is established on that connection and then the function will access a memory buffer that might be freed. When using that memory, libcurl might even call a function pointer in the object, making it possible for a remote code execution if the server could somehow manage to get crafted memory content into the correct place in memory.
Is CVE-2021-22901 exploited?
Not in the CISA KEV catalog.
EPSS puts exploitation in the next 30 days at 60%.
Public exploit code: none found in monitored sources.
Which products and versions are affected?
No affected package list recorded here yet.
Is there a patch?
No patch identifier recorded here yet.
What PlainSec published about CVE-2021-22901
PlainSec has not published a story about this CVE.