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CVE-2021-47755

8.7
High
EPSS 0.83%Jan 16, 2026

Unauthenticated file download in Oliver Library Server v5 via FileServlet

common questions

Is CVE-2021-47755 being exploited?

Not confirmed. CVE-2021-47755 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.83% probability of exploitation in the next 30 days.

How severe is CVE-2021-47755?

CVE-2021-47755 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2021-47755?

Not known from our data. No patch reference has been recorded for CVE-2021-47755, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.

What does CVE-2021-47755 affect?

CVE-2021-47755 affects Oliver Library Server v5 (FileServlet). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2021-47755?

Apply vendor patch/upgrade when available

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Oliver Library Server v5 (FileServlet)
impact

Unauthenticated read of arbitrary server files via fileName parameter in FileServlet.

action required

Patch when possible

affected versions
Softlink Education Oliver Library Server
  • affected< 8.00.008.053

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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