What is CVE-2019-18799?

CVE-2019-18799 is a medium-severity vulnerability in Sass-Lang Libsass, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2019-11-06.

How severe is CVE-2019-18799?

Medium severity. CVSS v3 base score is 6.5 out of 10.

NULL pointer dereference in Sass-Lang Libsass

CVE-2019-18799

LibSass before 3.6.3 allows a NULL pointer dereference in Sass::Parser::parseCompoundSelector in parser_selectors.cpp.

Published 2019-11-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.013 (68.2th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 68.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

Sass-Lang Libsass

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

github.com/sass/libsass/issues/3001 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2019-18799?: CVE-2019-18799 is a medium-severity vulnerability in Sass-Lang Libsass, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2019-11-06.
How severe is CVE-2019-18799?: Medium severity. CVSS v3 base score is 6.5 out of 10.