CVE-2020-1967

high-risk
Published 2020-04-21

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

Do I need to act?

!
67.3% chance of exploitation in next 30 days
EPSS score — higher than 33% of all CVEs
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

References (64)

and 44 more references
68
/ 100
high-risk
Severity 26/34 · High
Exploitability 19/34 · Moderate
Exposure 23/34 · High