What is CVE-2017-2624?

CVE-2017-2624 is a medium-severity vulnerability in X.org X Server, classified under CWE-385. CVSS score: 5.9/10. Published 2018-07-27.

How severe is CVE-2017-2624?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Is CVE-2017-2624 known to be exploited?

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

Information disclosure in X.org X Server

CVE-2017-2624

It was found that xorg-x11-server before 1.19.0 including uses memcmp() to check the received MIT cookie against a series of valid cookies. If the cookie is correct, it is allowed to attach to the Xorg session. Since most memcmp() implementations return after an invalid byte is seen, this causes a time difference between a valid and invalid byte, which could allow an efficient brute force attack.

Published 2018-07-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.007 (50.3th percentile), scored 2026-10-07.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

X.org X Server
Xorg Xorg-X11-Server — versions 1.19.0
Debian Linux — versions 7.0

Weakness classification (CWE)

Public proof-of-concept exploits

References

security.gentoo.org/glsa/201704-03 (vendor-advisory, Third Party Advisory)
gitlab.freedesktop.org/xorg/xserver/commit/d7ac755f0b618eb1259d93c8a16ec6e39a18… (Patch, Third Party Advisory)
www.securitytracker.com/id/1037919 (VDB Entry, Third Party Advisory, vdb-entry)
lists.debian.org/debian-lts-announce/2017/11/msg00032.html (mailing-list, Third Party Advisory)
security.gentoo.org/glsa/201710-30 (vendor-advisory, Third Party Advisory)
www.securityfocus.com/bid/96480 (VDB Entry, Third Party Advisory, vdb-entry)
www.x41-dsec.de/lab/advisories/x41-2017-001-xorg/ (Exploit, Third Party Advisory)
bugzilla.redhat.com/show_bug.cgi (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2017-2624?: CVE-2017-2624 is a medium-severity vulnerability in X.org X Server, classified under CWE-385. CVSS score: 5.9/10. Published 2018-07-27.
How severe is CVE-2017-2624?: Medium severity. CVSS v3 base score is 5.9 out of 10.
Is CVE-2017-2624 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.