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Fencer Intel
medium 6.5

CVE-2018-19837 json

In LibSass prior to 3.5.5, Sass::Eval::operator()(Sass::Binary_Expression*) inside eval.cpp allows attackers to cause a denial-of-service r…

published 7y ago modified 4mo ago also EUVD-2018-11512

cvss
6.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

In LibSass prior to 3.5.5, Sass::Eval::operator()(Sass::Binary_Expression*) inside eval.cpp allows attackers to cause a denial-of-service resulting from stack consumption via a crafted sass file, because of certain incorrect parsing of '%' as a modulo operator in parser.cpp.

Patch / fix

  • sass-lang libsass 3.5.5
  • libsass Debian 14, Debian 13, Debian 12 3.5.4+20180621~c0a6cf3-1

debian advisories DEBIAN-CVE-2018-19837

  • 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

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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-2018-19837 updated cvss 3.3

libsass: Stack consumption in Sass::Eval::operator() 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

1.80% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/sass/libsass/commit/210fdff7a65370c2ae24e022a2b35da8c423cc5f 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 Intel 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.