What is CVE-2017-9847?

CVE-2017-9847 is a medium-severity vulnerability in Libtorrent, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2017-06-24.

How severe is CVE-2017-9847?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Out-of-bounds Read in Libtorrent

CVE-2017-9847

The bdecode function in bdecode.cpp in libtorrent 1.1.3 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file.

Vulnerability class: Buffer Overflow

Published 2017-06-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.011 (63.6th percentile), scored 2026-10-07.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 63.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: -0.000

Affected products

Libtorrent — versions 1.1.3

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

github.com/arvidn/libtorrent/issues/2099 (Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2017-9847?: CVE-2017-9847 is a medium-severity vulnerability in Libtorrent, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2017-06-24.
How severe is CVE-2017-9847?: Medium severity. CVSS v3 base score is 5.5 out of 10.