CVE-2023-5748

Local service interruption via unchecked buffer copy

Published Oct 24, 2023 · Updated Sep 17, 2024

Classic buffer overflow in the cgi component of Synology SSL VPN Client before 1.4.7-0687 allows local users to interrupt the client. The cgi component copies input without checking its size; Synology has not disclosed the affected routine, input, or triggering vector. Low-privileged local access is required, and the published impact is limited to availability with no confidentiality or integrity effect.

CVSS severity3.3
Low
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Classic buffer overflow in the cgi component of Synology SSL VPN Client before 1.4.7-0687 allows local users to interrupt the client. The cgi component copies input without checking its size; Synology has not disclosed the affected routine, input, or triggering vector. Low-privileged local access is required, and the published impact is limited to availability with no confidentiality or integrity effect.

The record

CVE
CVE-2023-5748
Published
Oct 24, 2023
Updated
Sep 17, 2024
Vendor
Synology
Product
Synology SSL VPN Client
Classifications
CWE-120, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=* <1.4.7-0687

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Synology · Synology SSL VPN Clientversion=* <1.4.7-0687

Published CVSS scores

3.3Synology Inc.CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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