How severe is CVE-2018-20821?

CVE-2018-20821 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-20821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20821?

CVE-2018-20821 affects Sass-lang Libsass. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-20821?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-20821 published?

CVE-2018-20821 was published on 2019-04-23 and last updated on 2026-06-17.

CVE-2018-20821

CVE-2018-20821 is a medium-severity vulnerability in Sass-lang Libsass with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-674.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.3
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-674
Affected product: Sass-lang Libsass
Published: 2019-04-23
Last modified: 2026-06-17

Description

The parsing component in LibSass through 3.5.5 allows attackers to cause a denial-of-service (uncontrolled recursion in Sass::Parser::parse_css_variable_value in parser.cpp).

Frequently asked questions

What is CVE-2018-20821?: The parsing component in LibSass through 3.5.5 allows attackers to cause a denial-of-service (uncontrolled recursion in Sass::Parser::parse_css_variable_value in parser.cpp).
How severe is CVE-2018-20821?: CVE-2018-20821 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-20821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20821?: CVE-2018-20821 affects Sass-lang Libsass. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-20821?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-20821 published?: CVE-2018-20821 was published on 2019-04-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:sass-lang:libsass:*:*:*:*:*:*:*:*

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