CVE-2021-34811

MEDIUMNVD 5.05.0—

5.0

Server-Side Request Forgery (SSRF) vulnerability in task management component in Synology Download Station before 3.8.16-3566 allows remote authenticated users to access intranet resources via unspecified vectors.

CVSS v3: 5.0
EG Score: 5.0(medium)
EPSS: 44.0%
KEV: Not listed

Published

June 18, 2021

Last Modified

November 21, 2024

References (2)

security@synologyhttps://www.synology.com/security/advisory/Synology_SA_21_11
af854a3a-2127-422b-91ae-364da2661108https://www.synology.com/security/advisory/Synology_SA_21_11

Weakness Classification(1)

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

CWE-918Server-Side Request Forgery (SSRF)

Data Freshness Timeline

(refreshed 12× in last 7d / 20× 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.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
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
2026-05-27 13:39 UTCepss_batch
2026-05-26 14:46 UTCEG score recompute
2026-05-26 14:46 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-34811?

CVE-2021-34811 is a medium vulnerability published on June 18, 2021. Server-Side Request Forgery (SSRF) vulnerability in task management component in Synology Download Station before 3.8.16-3566 allows remote authenticated users to access intranet resources via unspecified vectors.

When was CVE-2021-34811 disclosed?

CVE-2021-34811 was first published in the National Vulnerability Database on June 18, 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-2021-34811 actively exploited?

CVE-2021-34811 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 44.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-34811?

CVE-2021-34811 has a CVSS v3 base score of 5.0 (NVD).

How do I remediate CVE-2021-34811?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-34811, 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

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CVE-2021-34811

📅 Published

🔄 Last Modified

🔗 References (2)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-34811?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (2)

Frequently asked(5)

Related CVEs(same CWE)