CVE-2023-5363Network attack vector

Confidentiality loss via ignored cipher length parameters

Published Oct 24, 2023 · Updated Jul 14, 2026

Incorrect cipher initialization in OpenSSL 3.0.0 through 3.0.11 and 3.1.0 through 3.1.3 allows attackers to expose data via unspecified vectors. EVP_EncryptInit_ex2, EVP_DecryptInit_ex2, and EVP_CipherInit_ex2 establish the key and IV before processing OSSL_PARAM keylen or ivlen changes, causing truncation or overreading. Exposure requires an application to change those lengths through the affected APIs; SSL/TLS and the OpenSSL 3.0 and 3.1 FIPS providers are unaffected.

CVSS severity7.5
High
EPSS probability3.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect cipher initialization in OpenSSL 3.0.0 through 3.0.11 and 3.1.0 through 3.1.3 allows attackers to expose data via unspecified vectors. EVP_EncryptInit_ex2, EVP_DecryptInit_ex2, and EVP_CipherInit_ex2 establish the key and IV before processing OSSL_PARAM keylen or ivlen changes, causing truncation or overreading. Exposure requires an application to change those lengths through the affected APIs; SSL/TLS and the OpenSSL 3.0 and 3.1 FIPS providers are unaffected.

The record

CVE
CVE-2023-5363
Published
Oct 24, 2023
Updated
Jul 14, 2026
Vendor
Siemens
Product
SINEC NMS
Classifications
CWE-684
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 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=0 <V3.0 SP1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SINEC NMSversion=0 <V3.0 SP1
Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
OpenSSL Project · OpenSSLversion=3.0.0 <3.0.12; version=3.1.0 <3.1.4
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIDIS Primeversion=0 <V4.0.700

Published CVSS scores

7.5OpenSSL Software FoundationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 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

CWE-684Incorrect Provision of Specified Functionality

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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