Use After Free in Openssl

CVE-2016-6309

statem/statem.c in OpenSSL 1.1.0a does not consider memory-block movement after a realloc call, which allows remote attackers to cause a denial of service (use-after-free) or possibly execute arbitrary code via a crafted TLS session.

Vulnerability class: Use-After-Free

EPSS: 0.697 (99.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

  • Openssl — versions 1.1.0a
  • N/a — versions n/a

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2016-6309?
CVE-2016-6309 is a critical-severity vulnerability in Openssl, classified under Use After Free. CVSS score: 9.8/10. Published 2016-09-26.
How severe is CVE-2016-6309?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2016-6309 known to be exploited?
39 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.