What is CVE-2017-12940?

CVE-2017-12940 is a critical-severity vulnerability in Rarlab Unrar, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2017-08-18.

How severe is CVE-2017-12940?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Out-of-bounds Read in Rarlab Unrar

CVE-2017-12940

libunrar.a in UnRAR before 5.5.7 has an out-of-bounds read in the EncodeFileName::Decode call within the Archive::ReadHeader15 function.

Vulnerability class: Buffer Overflow

Published 2017-08-18 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.022 (81.8th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 81.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.023 · newest: 0.022 · change: -0.001

Affected products

Rarlab Unrar

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

seclists.org/oss-sec/2017/q3/290 (Exploit, Mailing List, Third Party Advisory)
kc.mcafee.com/corporate/index
security.gentoo.org/glsa/201709-24 (vendor-advisory)

Frequently asked questions

What is CVE-2017-12940?: CVE-2017-12940 is a critical-severity vulnerability in Rarlab Unrar, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2017-08-18.
How severe is CVE-2017-12940?: Critical severity. CVSS v3 base score is 9.8 out of 10.