CVE-2021-34812Network attack vector

Sensitive-information disclosure via hard-coded PHP credentials

Published Jun 18, 2021 · Updated Sep 17, 2024

Hard-coded credentials in the PHP component of Synology Calendar before 2.4.0-0761 allow remote attackers to obtain sensitive information. The PHP component embeds credentials that bypass security constraints, but Synology has not published their location or the request that consumes them. No authentication or user interaction is required; the documented impact is limited to information disclosure, with no integrity or availability effect.

CVSS severity5.8
Medium
EPSS probability1.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hard-coded credentials in the PHP component of Synology Calendar before 2.4.0-0761 allow remote attackers to obtain sensitive information. The PHP component embeds credentials that bypass security constraints, but Synology has not published their location or the request that consumes them. No authentication or user interaction is required; the documented impact is limited to information disclosure, with no integrity or availability effect.

The record

CVE
CVE-2021-34812
Published
Jun 18, 2021
Updated
Sep 17, 2024
Vendor
Synology
Product
Synology Calendar
Classifications
CWE-798
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2021CVE 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=unspecified <2.4.0-0761

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Synology · Synology Calendarversion=unspecified <2.4.0-0761

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.8SynologyCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

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.

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No observations available

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

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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