CVE-2026-15638Network attack vector

Data decryption and encryption via padding oracle

Published Sep 15, 2026 · Updated Sep 15, 2026

Cryptographic flaw in Delinea Secret Server On-Premises 10.5.1 through 12.1.3 allows remote attackers to decrypt or encrypt data. The server exposes a padding-validity oracle while processing attacker-supplied ciphertext with a server cryptographic key; the affected endpoint is undisclosed. Exploitation requires unauthenticated network access to Secret Server and can expose or modify protected data without revealing the key itself.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic flaw in Delinea Secret Server On-Premises 10.5.1 through 12.1.3 allows remote attackers to decrypt or encrypt data. The server exposes a padding-validity oracle while processing attacker-supplied ciphertext with a server cryptographic key; the affected endpoint is undisclosed. Exploitation requires unauthenticated network access to Secret Server and can expose or modify protected data without revealing the key itself.

The record

CVE
CVE-2026-15638
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
Delinea
Product
Secret Server On-Premises
Classifications
T1555.005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2026Record 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=10.5.1 <=12.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Delinea · Secret Server On-Premisesversion=10.5.1 <=12.1.3

Published CVSS scores

No CVSS assessment is available in this record.

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1555.005Credentials from Password Stores: Password Managers

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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