CVE-2021-30481

HIGHNVD 8.09.0▲Trending — 3 sources updated this week

8.0

Valve Steam before 2021-04-17, when a Source engine game is installed, allows remote authenticated users to execute arbitrary code because of a buffer overflow that occurs for a Steam invite after one click.

CVSS v3: 8.0
EG Score: 9.0(medium)
EPSS: 91.5%
KEV: Not listed

Published

April 10, 2021

Last Modified

November 3, 2025

References (8)

cve@mitrehttps://news.ycombinator.com/item?id=26762170
cve@mitrehttps://twitter.com/floesen_/status/1337107178096881666
cve@mitrehttps://twitter.com/the_secret_club/status/1380868759129296900
cve@mitrehttps://www.youtube.com/watch?v=rNQn--9xR1Q
af854a3a-2127-422b-91ae-364da2661108https://news.ycombinator.com/item?id=26762170
af854a3a-2127-422b-91ae-364da2661108https://twitter.com/floesen_/status/1337107178096881666
af854a3a-2127-422b-91ae-364da2661108https://twitter.com/the_secret_club/status/1380868759129296900
af854a3a-2127-422b-91ae-364da2661108https://www.youtube.com/watch?v=rNQn--9xR1Q

Weakness Classification(1)

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

CWE-120Buffer Copy without Checking Size (Classic Buffer Overflow)

Data Freshness Timeline

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

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 18:30 UTCEG score recompute
2026-05-26 18:30 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch

Frequently asked(5)

What is CVE-2021-30481?

CVE-2021-30481 is a high vulnerability published on April 10, 2021. Valve Steam before 2021-04-17, when a Source engine game is installed, allows remote authenticated users to execute arbitrary code because of a buffer overflow that occurs for a Steam invite after one click.

When was CVE-2021-30481 disclosed?

CVE-2021-30481 was first published in the National Vulnerability Database on April 10, 2021, with the most recent update on November 3, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-30481 actively exploited?

CVE-2021-30481 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 91.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-30481?

CVE-2021-30481 has a CVSS v3 base score of 8.0 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.

How do I remediate CVE-2021-30481?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-30481, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-30481

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CVE-2021-30481

📅 Published

🔄 Last Modified

🔗 References (8)