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.

EPSS: 0.007 (48.3th percentile) — read the EPSS interpretation.

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.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

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.