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Fencer Vulns
medium 6.5

CVE-2019-18798 json

LibSass before 3.6.3 allows a heap-based buffer over-read in Sass::weaveParents in ast_sel_weave.cpp.

published 2019-11-06 7 y ago modified 2026-07-25 3 mo ago also EUVD-2019-8503 , JLSEC-2026-506

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

LibSass before 3.6.3 allows a heap-based buffer over-read in Sass::weaveParents in ast_sel_weave.cpp.

Patch / fix

  • julia libsass_jll 3.6.4+0
  • sass-lang libsass 3.6.3
  • libsass Debian 14, Debian 13, Debian 12 3.6.3-1

debian advisories DEBIAN-CVE-2019-18798

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-2019-18798 updated cvss 6.5

libsass: heap-based buffer overflow in Sass:weaveParents in ast_sel_weave.cpp

  • 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

1.05% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sass/libsass/issues/2999 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.