What is CVE-2017-16956?

CVE-2017-16956 is a medium-severity vulnerability in Symphony Project, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2017-11-27.

How severe is CVE-2017-16956?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Symphony Project

CVE-2017-16956

b3log Symphony (aka Sym) 2.2.0 allows an XSS attack by sending a private letter with a certain /article URI, and a second private letter with a modified title.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2017-11-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (54.3th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.3% 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

Symphony Project — versions 2.2.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/b3log/symphony/issues/509 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2017-16956?: CVE-2017-16956 is a medium-severity vulnerability in Symphony Project, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2017-11-27.
How severe is CVE-2017-16956?: Medium severity. CVSS v3 base score is 6.1 out of 10.