CVE-2018-19839

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to...

6.5 MediumFix available

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

2.16%Up 0.9 points since Apr 14, 2021

What each source reports

NVD Score used 6.5

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: CVE-2018-19839
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness: CWE-125
Updated: 2026-11-02

CVE List No score

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: CVE-2018-19839
Updated: 2026-11-02

EUVDEUVD-2018-11514 No score

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: EUVD-2018-11514
Updated: 2026-11-03

GitHub AdvisoriesGHSA-pfp7-r6qm-94j7 6.5

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to...

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: GHSA-pfp7-r6qm-94j7
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-125
Updated: 2026-11-02

OSV 6.5

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: CVE-2018-19839
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2018-19839 6.5

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: DEBIAN-CVE-2018-19839
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

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OSVUBUNTU-CVE-2018-19839 6.5

In LibSass prior to 3.5.5, the function handle_error in sass_context.cpp allows attackers to cause a denial-of-service resulting from a heap-based buffer over-read via a crafted sass file.

Record: UBUNTU-CVE-2018-19839
CVSS 3.0: 6.5 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVMGASA-2020-0049 No score

Updated libsass packages fix security vulnerabilities

Use-after-free vulnerability in sass_context.cpp:handle_error (CVE-2018-11499).

Null pointer dereference in Sass::Selector_List::populate_extends (CVE-2018-19797).

Use-after-free vulnerability exists in the SharedPtr class (CVE-2018-19827).

Stack overflow in Eval::operator() (CVE-2018-19837).

Stack-overflow at IMPLEMENT_AST_OPERATORS expansion (CVE-2018-19838).

Buffer-overflow (OOB read) against some invalid input (CVE-2018-19839).

Null pointer dereference in Sass::Eval::operator() (Sass::Supports_Operator*) (CVE-2018-20190).

Uncontrolled recursion in Sass:Parser:parse_css_variable_value (CVE-2018-20821).

Stack-overflow at Sass::Inspect::operator() (CVE-2018-20822).

Heap-buffer-overflow in Sass::Prelexer::parenthese_scope(char const*) (CVE-2019-6283).

Heap-based buffer over-read exists in Sass:Prelexer:alternatives (CVE-2019-6284).

Heap-based buffer over-read exists in Sass:Prelexer:skip_over_scopes (CVE-2019-6286).

Record: MGASA-2020-0049
Updated: 2026-11-02

OSVopenSUSE-SU-2019:1791-1 No score

Security update for libsass

This update for libsass to version 3.6.1 fixes the following issues:

Security issues fixed:

CVE-2019-6283: Fixed heap-buffer-overflow in Sass::Prelexer::parenthese_scope(char const*) (boo#1121943).
CVE-2019-6284: Fixed heap-based buffer over-read exists in Sass:Prelexer:alternatives (boo#1121944).
CVE-2019-6286: Fixed heap-based buffer over-read exists in Sass:Prelexer:skip_over_scopes (boo#1121945).
CVE-2018-11499: Fixed use-after-free vulnerability in sass_context.cpp:handle_error (boo#1096894).
CVE-2018-19797: Disallowed parent selector in selector_fns arguments (boo#1118301).
CVE-2018-19827: Fixed use-after-free vulnerability exists in the SharedPtr class (boo#1118346).
CVE-2018-19837: Fixed stack overflow in Eval::operator() (boo#1118348).
CVE-2018-19838: Fixed stack-overflow at IMPLEMENT_AST_OPERATORS expansion (boo#1118349).
CVE-2018-19839: Fixed buffer-overflow (OOB read) against some invalid input (boo#1118351).
CVE-2018-20190: Fixed Null pointer dereference in Sass::Eval::operator()(Sass::Supports_Operator*) (boo#1119789).
CVE-2018-20821: Fixed uncontrolled recursion in Sass:Parser:parse_css_variable_value (boo#1133200).
CVE-2018-20822: Fixed stack-overflow at Sass::Inspect::operator() (boo#1133201).

Record: openSUSE-SU-2019:1791-1
Updated: 2026-11-02

OSVopenSUSE-SU-2019:1800-1 No score

Security update for libsass

This update for libsass to version 3.6.1 fixes the following issues:

Security issues fixed:

CVE-2019-6283: Fixed heap-buffer-overflow in Sass::Prelexer::parenthese_scope(char const*) (boo#1121943).
CVE-2019-6284: Fixed heap-based buffer over-read exists in Sass:Prelexer:alternatives (boo#1121944).
CVE-2019-6286: Fixed heap-based buffer over-read exists in Sass:Prelexer:skip_over_scopes (boo#1121945).
CVE-2018-11499: Fixed use-after-free vulnerability in sass_context.cpp:handle_error (boo#1096894).
CVE-2018-19797: Disallowed parent selector in selector_fns arguments (boo#1118301).
CVE-2018-19827: Fixed use-after-free vulnerability exists in the SharedPtr class (boo#1118346).
CVE-2018-19837: Fixed stack overflow in Eval::operator() (boo#1118348).
CVE-2018-19838: Fixed stack-overflow at IMPLEMENT_AST_OPERATORS expansion (boo#1118349).
CVE-2018-19839: Fixed buffer-overflow (OOB read) against some invalid input (boo#1118351).
CVE-2018-20190: Fixed Null pointer dereference in Sass::Eval::operator()(Sass::Supports_Operator*) (boo#1119789).
CVE-2018-20821: Fixed uncontrolled recursion in Sass:Parser:parse_css_variable_value (boo#1133200).
CVE-2018-20822: Fixed stack-overflow at Sass::Inspect::operator() (boo#1133201).

This update was imported from the openSUSE:Leap:15.0:Update update project.

Record: openSUSE-SU-2019:1800-1
Updated: 2026-11-02

OSVopenSUSE-SU-2019:1883-1 No score

Security update for libsass

This update for libsass to version 3.6.1 fixes the following issues:

Security issues fixed:

CVE-2019-6283: Fixed heap-buffer-overflow in Sass::Prelexer::parenthese_scope(char const*) (boo#1121943).
CVE-2019-6284: Fixed heap-based buffer over-read exists in Sass:Prelexer:alternatives (boo#1121944).
CVE-2019-6286: Fixed heap-based buffer over-read exists in Sass:Prelexer:skip_over_scopes (boo#1121945).
CVE-2018-11499: Fixed use-after-free vulnerability in sass_context.cpp:handle_error (boo#1096894).
CVE-2018-19797: Disallowed parent selector in selector_fns arguments (boo#1118301).
CVE-2018-19827: Fixed use-after-free vulnerability exists in the SharedPtr class (boo#1118346).
CVE-2018-19837: Fixed stack overflow in Eval::operator() (boo#1118348).
CVE-2018-19838: Fixed stack-overflow at IMPLEMENT_AST_OPERATORS expansion (boo#1118349).
CVE-2018-19839: Fixed buffer-overflow (OOB read) against some invalid input (boo#1118351).
CVE-2018-20190: Fixed Null pointer dereference in Sass::Eval::operator()(Sass::Supports_Operator*) (boo#1119789).
CVE-2018-20821: Fixed uncontrolled recursion in Sass:Parser:parse_css_variable_value (boo#1133200).
CVE-2018-20822: Fixed stack-overflow at Sass::Inspect::operator() (boo#1133201).

This update was imported from the openSUSE:Leap:15.0:Update update project.

Record: openSUSE-SU-2019:1883-1
Updated: 2026-11-02

OSVopenSUSE-SU-2024:10988-1 No score

libsass-3_6_5-1-3.6.5-1.2 on GA media

These are all security issues fixed in the libsass-3_6_5-1-3.6.5-1.2 package on the GA media of openSUSE Tumbleweed.

Record: openSUSE-SU-2024:10988-1
Updated: 2026-11-02

OSVUSN-4837-1 No score

libsass vulnerabilities

It was discovered that LibSass incorrectly handled certain specially crafted sass file. An attacker could possibly use this issue to cause a denial of service or other unspecified impact.

Record: USN-4837-1
Updated: 2026-11-02

Affected products

sass-lang libsass

Affected packages

Affected packages
Package	Affected	Fixed
`libsass` Debian:12	before 3.5.5-4	3.5.5-4
`libsass` Debian:13	before 3.5.5-4	3.5.5-4
`libsass` Debian:14	before 3.5.5-4	3.5.5-4
`libsass` Mageia:7 From an advisory covering 12 CVEs	before 3.6.1-1.mga7	3.6.1-1.mga7
`libsass` Ubuntu:16.04:LTS	All versions, plus listed versions 3.2.5-13.2.5-23.3.2-13.3.4-1	None known
`libsass` Ubuntu:Pro:18.04:LTS	before 3.4.8-1ubuntu0.1~esm1, plus listed versions 3.4.3-13.4.6-13.4.8-1	3.4.8-1ubuntu0.1~esm1
`libsass` Ubuntu:Pro:18.04:LTS From an advisory covering 13 CVEs	before 3.4.8-1ubuntu0.1~esm1, plus listed versions 3.4.3-13.4.6-13.4.8-1	3.4.8-1ubuntu0.1~esm1
`libsass` openSUSE:Leap 15.0 From an advisory covering 12 CVEs	before 3.6.1-lp151.3.3.1	3.6.1-lp151.3.3.1
`libsass` openSUSE:Leap 15.1 From an advisory covering 12 CVEs	before 3.6.1-lp151.3.3.1	3.6.1-lp151.3.3.1
`libsass` SUSE:Package Hub 15 From an advisory covering 12 CVEs	before 3.6.1-bp150.3.3.1	3.6.1-bp150.3.3.1
`libsass` SUSE:Package Hub 15 SP1 From an advisory covering 12 CVEs	before 3.6.1-bp151.4.3.1	3.6.1-bp151.4.3.1

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-19839 is a medium vulnerability (CVSS 6.5) in Sass-lang Libsass, published December 4, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.16%, the 82nd percentile. Fixed in libsass 3.5.5-4.

References

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