CVE-2021-41168

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 59% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Snudown is a reddit-specific fork of the Sundown Markdown parser used by GitHub, with Python integration added. In affected versions snudown was found to be vulnerable to denial of service attacks to its reference table implementation. References written in markdown [reference_name]: https://www.example.com are inserted into a hash table which was found to have a weak hash function, meaning that an attacker can reliably generate a large number of collisions for it. This makes the hash table vulnerable to a hash-collision DoS attack, a type of algorithmic complexity attack. Further the hash table allowed for duplicate entries resulting in long retrieval times. Proofs of concept and further discussion of the hash collision issue are discussed on the snudown GHSA(https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6). Users are advised to update to version 1.7.0.

CVSS v3
6.5
EG Score
6.5(medium)
EPSS
54.9%
KEV
Not listed

Published

October 21, 2021

Last Modified

November 21, 2024

References (4)

Weakness Classification(4)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 50× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

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Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-41168?
CVE-2021-41168 is a medium vulnerability published on October 21, 2021. Snudown is a reddit-specific fork of the Sundown Markdown parser used by GitHub, with Python integration added. In affected versions snudown was found to be vulnerable to denial of service attacks to its reference table implementation. References written in markdown [reference_name]:…
When was CVE-2021-41168 disclosed?
CVE-2021-41168 was first published in the National Vulnerability Database on October 21, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-41168 actively exploited?
CVE-2021-41168 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 54.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-41168?
CVE-2021-41168 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2021-41168?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-41168, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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