Constructed ASN.1 types with a recursive definition could exceed the stack

Summary

Constructed ASN.1 types with a recursive definition (such as can be found in PKCS7) could eventually exceed the stack given malicious input with excessive recursion. This could result in a Denial Of Service attack. There are no such structures used within SSL/TLS that come from untrusted sources so this is considered safe. Fixed in OpenSSL 1.1.0h (Affected 1.1.0-1.1.0g). Fixed in OpenSSL 1.0.2o (Affected 1.0.2b-1.0.2n).

Timeline

1. Mar 27, 2018, 9:00 PM UTCCVE published
2. Sep 16, 2024, 10:35 PM UTCRecord last updated
3. Oct 28, 2026EPSS reached 10%

   FIRST estimates at least a 10% chance of exploitation in the next 30 days

Affected versions

• OpenSSL OpenSSL

  Fixed in OpenSSL 1.1.0h (Affected 1.1.0-1.1.0g), Fixed in OpenSSL 1.0.2o (Affected 1.0.2b-1.0.2n)

References 25