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Fencer Vulns
medium 6.5

CVE-2019-6284 json

In LibSass 3.5.5, a heap-based buffer over-read exists in Sass::Prelexer::alternatives in prelexer.hpp.

published 2019-01-14 7 y ago modified 2026-07-18 3 mo ago also EUVD-2019-15850 , JLSEC-2026-509

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

In LibSass 3.5.5, a heap-based buffer over-read exists in Sass::Prelexer::alternatives in prelexer.hpp.

Patch / fix

  • julia libsass_jll 3.6.4+0
  • libsass Debian 14, Debian 13, Debian 12 3.5.5-3

debian advisories DEBIAN-CVE-2019-6284

  • libsass Ubuntu Pro 18.04 LTS 3.4.8-1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2019-6284

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • 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-2019-6284 updated cvss 3.3

libsass: heap-based buffer over-read in Sass::Prelexer::alternatives in prelexer.hpp

  • Red Hat Enterprise Linux 8 libsass
    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

2.01% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sass/libsass/issues/2816 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/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
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia libsass_jll
<3.6.4+0
3.6.4+0

Classification

Weakness

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.