What is CVE-2017-8420?

CVE-2017-8420 is a medium-severity vulnerability in Microsoft Windows, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 6.5/10. Published 2017-07-05.

How severe is CVE-2017-8420?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Buffer overflow in Microsoft Windows

CVE-2017-8420

SWFTools 2013-04-09-1007 on Windows has a "Data from Faulting Address controls Branch Selection starting at image00000000_00400000+0x0000000000003e71" issue. This issue can be triggered by a malformed TTF file that is mishandled by font2swf. Attackers could exploit this issue for DoS (Access Violation).

Vulnerability class: Buffer Overflow

Published 2017-07-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.009 (57.6th percentile), scored 2026-10-06.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 57.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Microsoft Windows
Swftools — versions 2013-04-09-1007

Weakness classification (CWE)

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

References

github.com/wlinzi/security_advisories/tree/master/CVE-2017-8420 (Third Party Advisory)

Frequently asked questions

What is CVE-2017-8420?: CVE-2017-8420 is a medium-severity vulnerability in Microsoft Windows, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 6.5/10. Published 2017-07-05.
How severe is CVE-2017-8420?: Medium severity. CVSS v3 base score is 6.5 out of 10.