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Fencer Vulns
medium 6.5

CVE-2018-19838 json

In LibSass prior to 3.5.5, functions inside ast.cpp for IMPLEMENT_AST_OPERATORS expansion allow attackers to cause a denial-of-service resu…

published 2018-12-04 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-11513

cvss
6.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

In LibSass prior to 3.5.5, functions inside ast.cpp for IMPLEMENT_AST_OPERATORS expansion allow attackers to cause a denial-of-service resulting from stack consumption via a crafted sass file, as demonstrated by recursive calls involving clone(), cloneChildren(), and copy().

Patch / fix

  • sass-lang libsass 3.5.5
  • libsass Debian 14, Debian 13, Debian 12 3.6.3-1

debian advisories DEBIAN-CVE-2018-19838

  • libsass Package Hub 15 SP1 3.6.1-bp151.4.3.1
  • libsass Package Hub 15 3.6.1-bp150.3.3.1
  • libsass openSUSE Leap 15.1, openSUSE Leap 15.0 3.6.1-lp151.3.3.1

opensuse advisories openSUSE-SU-2019:1883-1openSUSE-SU-2019:1800-1openSUSE-SU-2019:1791-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-19838 updated cvss 3.3

libsass: Stack consumption in ast.cpp resulting in a denial of service

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.93% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sass/libsass/issues/2660 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.