How severe is CVE-2020-5238?

CVE-2020-5238 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-5238 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5238?

CVE-2020-5238 primarily affects Github Flavored Markdown Project Github Flavored Markdown. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-5238?

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

When was CVE-2020-5238 published?

CVE-2020-5238 was published on 2020-07-01 and last updated on 2026-06-17.

CVE-2020-5238

CVE-2020-5238 is a medium-severity vulnerability in Github Flavored Markdown Project Github Flavored Markdown 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Github Flavored Markdown Project Github Flavored Markdown
Published: 2020-07-01
Last modified: 2026-06-17

Description

The table extension in GitHub Flavored Markdown before version 0.29.0.gfm.1 takes O(n * n) time to parse certain inputs. An attacker could craft a markdown table which would take an unreasonably long time to process, causing a denial of service. This issue does not affect the upstream cmark project. The issue has been fixed in version 0.29.0.gfm.1.

Frequently asked questions

What is CVE-2020-5238?: The table extension in GitHub Flavored Markdown before version 0.29.0.gfm.1 takes O(n * n) time to parse certain inputs. An attacker could craft a markdown table which would take an unreasonably long time to process, causing a denial of service. This issue does not affect the upstream cmark project. The issue has been fixed in version 0.29.0.gfm.1.
How severe is CVE-2020-5238?: CVE-2020-5238 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-5238 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5238?: CVE-2020-5238 primarily affects Github Flavored Markdown Project Github Flavored Markdown. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-5238?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-5238 published?: CVE-2020-5238 was published on 2020-07-01 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:github_flavored_markdown_project:github_flavored_markdown:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

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