What is CVE-2017-3735?

CVE-2017-3735 is a medium-severity vulnerability in OpenSSL, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.3/10. Published 2017-08-28.

How severe is CVE-2017-3735?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Is CVE-2017-3735 known to be exploited?

9 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in OpenSSL

CVE-2017-3735

While parsing an IPAddressFamily extension in an X.509 certificate, it is possible to do a one-byte overread. This would result in an incorrect text display of the certificate. This bug has been present since 2006 and is present in all versions of OpenSSL before 1.0.2m and 1.1.0g.

Vulnerability class: Buffer Overflow

Published 2017-08-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.210 (97.5th percentile), scored 2026-09-28.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 97.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.177 · newest: 0.210 · change: +0.033

Affected products

OpenSSL — versions 0.9.7j, 0.9.7k, 0.9.7l
OpenSSL Software Foundation — versions 1.0.2, 1.1.0
Debian Linux — versions 8.0, 9.0

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

Public proof-of-concept exploits

References

www.securitytracker.com/id/1039726 (VDB Entry, Third Party Advisory, vdb-entry)
usn.ubuntu.com/3611-2/ (vendor-advisory)
www.debian.org/security/2017/dsa-4018 (vendor-advisory, Third Party Advisory)
security.gentoo.org/glsa/201712-03 (vendor-advisory)
lists.debian.org/debian-lts-announce/2017/11/msg00011.html (mailing-list)
access.redhat.com/errata/RHSA-2018:3505 (vendor-advisory)
www.debian.org/security/2017/dsa-4017 (vendor-advisory, Third Party Advisory)
access.redhat.com/errata/RHSA-2018:3221 (vendor-advisory)
www.securityfocus.com/bid/100515 (VDB Entry, Third Party Advisory, vdb-entry)
security.FreeBSD.org/advisories/FreeBSD-SA-17:11.openssl.asc (vendor-advisory)

Frequently asked questions

What is CVE-2017-3735?: CVE-2017-3735 is a medium-severity vulnerability in OpenSSL, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.3/10. Published 2017-08-28.
How severe is CVE-2017-3735?: Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2017-3735 known to be exploited?: 9 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.