How severe is CVE-2020-25821?

CVE-2020-25821 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-25821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-25821?

CVE-2020-25821 affects Peg-markdown Project Peg-markdown. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-25821?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-25821 published?

CVE-2020-25821 was published on 2020-09-23 and last updated on 2026-06-17.

CVE-2020-25821

CVE-2020-25821 is a high-severity vulnerability in Peg-markdown Project Peg-markdown with a CVSS 3.x base score of 7.5. 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-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Peg-markdown Project Peg-markdown
Published: 2020-09-23
Last modified: 2026-06-17

Description

peg-markdown 0.4.14 has a NULL pointer dereference in process_raw_blocks in markdown_lib.c. NOTE: This vulnerability only affects products that are no longer supported by the maintainer

Frequently asked questions

What is CVE-2020-25821?: peg-markdown 0.4.14 has a NULL pointer dereference in process_raw_blocks in markdown_lib.c. NOTE: This vulnerability only affects products that are no longer supported by the maintainer
How severe is CVE-2020-25821?: CVE-2020-25821 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-25821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-25821?: CVE-2020-25821 affects Peg-markdown Project Peg-markdown. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-25821?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-25821 published?: CVE-2020-25821 was published on 2020-09-23 and last updated on 2026-06-17.

References

https://github.com/jgm/peg-markdown/issues/43

Affected products (1)

cpe:2.3:a:peg-markdown_project:peg-markdown:0.4.14:*:*:*:*:*:*:*

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