CVE-2023-27538

mediumpriority · track · 23EPSS 0.015 · 73 %ileDEEUFRRUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.45% (73rd) EPSS

CVSS 5.5 · medium

Is it mine?

87 products

Check your exposure

Who says so?

8 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if the configurations match. However, two SSH settings were omitted from the configuration check, allowing them to match easily, potentially leading to the reuse of an inappropriate connection.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedSINEC INSsiemens_psirt
Update to V1.0 SP2 Update 2 or later version
https://support.industry.siemens.com/cs/ww/en/view/109825710/
FixedSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)siemens_psirt
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)siemens_psirt
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)siemens_psirt
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)siemens_psirt
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)siemens_psirt
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSINEC NMSsiemens_psirt
Update to V2.0 SP1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109826954/
FixedSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)cisa_csaf_ot
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)cisa_csaf_ot
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)cisa_csaf_ot
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)cisa_csaf_ot
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)cisa_csaf_ot
Update to V3.1.5 or later version
https://support.industry.siemens.com/cs/ww/en/view/109478459/
FixedSINEC INScisa_csaf_ot
Update to V1.0 SP2 Update 2 or later version
https://support.industry.siemens.com/cs/ww/en/view/109825710/
FixedSINEC NMScisa_csaf_ot
Update to V2.0 SP1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109826954/
MitigationSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)cisa_csaf_ot
Only build and run applications from trusted sources.
MitigationSIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)cisa_csaf_ot
Only build and run applications from trusted sources.
MitigationSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)cisa_csaf_ot
Only build and run applications from trusted sources.
MitigationSIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)cisa_csaf_ot
Only build and run applications from trusted sources.
MitigationSIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)cisa_csaf_ot
Only build and run applications from trusted sources.
WorkaroundSINEC INSsiemens_psirt
Restrict access to application webserver for trusted users only
WorkaroundSINEC INScisa_csaf_ot
Restrict access to application webserver for trusted users only

cvss

Technical severity, 0–10. One row per scoring source.

7.7

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.1–7.7

v3.15.5mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 1.8 · impact 3.6

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:P/RL:O/RC:Csecondary · CISA US

v3.16.5mediumAV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondary · FSTEC (BDU) RU

v3.17.7highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Hsecondary · ENISA EU

v3.17.7highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Hsecondaryexploitability 2.5 · impact 5.2

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:P/RL:O/RC:Csecondary · Siemens ProductCERT DE

v3.15.1mediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-287USprimaryCWE-20USCWE-20USCWE-287USCWE-305USCWE-305US

affected products (87)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
Dell Avamarall versionscert_bundDEcpe:/a:dell:avamar:-
Dell Data Protection Advisor <19.12all versionscert_bundDE
Dell NetWorker <19.9.0.1all versionscert_bundDE
Dell NetWorker Virtual Editionall versionscert_bundDEcpe:/a:dell:networker:virtual_edition
F5 F5OSall versionscert_bundDEcpe:/o:f5:f5os:-
Fedora Linuxall versionscert_bundDEcpe:/o:fedoraproject:fedora:-
Gentoo Linuxall versionscert_bundDEcpe:/o:gentoo:linux:-
IBM AIX 7.3.1all versionscert_bundDEcpe:/o:ibm:aix:7.3.1
IBM QRadar SIEM 7.5all versionscert_bundDEcpe:/a:ibm:qradar_siem:7.5
IBM Spectrum Protect <plus 10.1.15.3all versionscert_bundDE
Meinberg LANTIME <V7.06.014all versionscert_bundDE
NetApp ActiveIQ Unified Managerall versionscert_bundDEcpe:/a:netapp:active_iq_unified_manager:-
NetApp Data ONTAPall versionscert_bundDEcpe:/a:netapp:data_ontap:-
NetApp Data ONTAP 9all versionscert_bundDEcpe:/a:netapp:data_ontap:9
Open Source cURL <8.0.0all versionscert_bundDE
Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
Red Hat OpenShift Container Platform <4.13.4all versionscert_bundDE

showing 20 of 87

advisories (15)

Vendor and ecosystem advisories describing this.

SSA-077170SSA-077170: Multiple Vulnerabilities in SINEC INS before V1.0 SP2 Update 22023-12-12csaf · siemens_psirtDE
SINEC INS before V1.0 SP2 Update 2 is affected by multiple vulnerabilities. Siemens has released an update for SINEC INS and recommends to update to the latest version.
SSA-398330SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.52023-12-12csaf · siemens_psirtDE
Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 are no longer maintained and there won't be any update to the CVE list anymore. Please update to the latest version. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 (https://cert-portal.siemens.com/productcert/html/ssb-439005.html).
SSA-943925SSA-943925: Multiple Vulnerabilities in SINEC NMS before V2.0 SP12024-02-13csaf · siemens_psirtDE
SINEC NMS before V2.0 SP1 is affected by multiple vulnerabilities. Siemens has released an update for SINEC NMS and recommends to update to the latest version.
WID-SEC-W-2023-0690cURL: Mehrere SchwachstellenDeutsch2023-03-19csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in cURL ausnutzen, um Informationen offenzulegen, Sicherheitsvorkehrungen zu umgehen oder unbekannte Auswirkungen zu verursachen.
WID-SEC-W-2023-1350Splunk Splunk Enterprise: Mehrere Schwachstellen in Komponenten von DrittanbieternDeutsch2023-06-01csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Splunk Splunk Enterprise in diversen Komponenten von Drittanbietern ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.
WID-SEC-W-2023-1614Tenable Security Nessus Network Monitor: Mehrere SchwachstellenDeutsch2023-06-29csaf · cert_bundDE
Ein entfernter, anonymer, authentisierter oder lokaler Angreifer kann mehrere Schwachstellen in Tenable Security Nessus Network Monitor ausnutzen, um beliebigen Code auszuführen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand auszulösen und Daten zu manipulieren.
WID-SEC-W-2023-2229Splunk Splunk Enterprise: Mehrere SchwachstellenDeutsch2023-08-30csaf · cert_bundDE
Ein entfernter, authentifizierter Angreifer kann mehrere Schwachstellen in Splunk Splunk Enterprise ausnutzen, um beliebigen Code auszuführen, einen 'Denial of Service'-Zustand zu verursachen, seine Privilegien zu erweitern und weitere, nicht spezifizierte Auswirkungen zu verursachen.
WID-SEC-W-2024-0794Dell ECS: Mehrere SchwachstellenDeutsch2024-04-04csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Dell ECS ausnutzen, um seine Privilegien zu erweitern, beliebigen Programmcode mit Administratorrechten auszuführen, Informationen offenzulegen, Dateien zu manipulieren, einen Cross-Site-Scripting-Angriff durchzuführen, Sicherheitsvorkehrungen zu umgehen oder einen Denial of Service Zustand herbeizuführen.
WID-SEC-W-2024-3377Dell PowerProtect Data Domain: Mehrere SchwachstellenDeutsch2024-11-07csaf · cert_bundDE
Ein lokaler Angreifer kann mehrere Schwachstellen in Dell PowerProtect Data Domain ausnutzen, um seine Privilegien zu erhöhen, Informationen offenzulegen und um nicht näher beschriebene Auswirkungen zu erzielen.
WID-SEC-W-2026-0180Dell Data Protection Advisor: Mehrere SchwachstellenDeutsch2026-01-20csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Dell Data Protection Advisor ausnutzen, um beliebigen Code auszuführen, einen Denial-of-Service-Zustand zu erzeugen, Sicherheitsmaßnahmen zu umgehen und nicht näher spezifizierte Angriffe zu starten.
ICSA-23-348-10Siemens SIMATIC S7-15002023-12-12icsa · cisa_csaf_otUS
Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version >= V3.1.0 and < V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant). These GNU/Linux vulnerabilities have been externally identified. Siemens has released new versions for the affected products and recommends to update to the latest versions. Note: This SSA advises vulnerabilities for firmware version V3.1 only; for versions < V3.1 refer to Siemens Security Bulletin SSB-439005 ( https://cert-portal.siemens.com/productcert/html/ssb-439005.html).
ICSA-23-348-16Siemens SINEC INS2023-12-12icsa · cisa_csaf_otUS
SINEC INS before V1.0 SP2 Update 2 is affected by multiple vulnerabilities. Siemens has released an update for SINEC INS and recommends to update to the latest version.
ICSA-24-046-15Siemens SINEC NMS2024-02-13icsa · cisa_csaf_otUS
SINEC NMS before V2.0 SP1 is affected by multiple vulnerabilities. Siemens has released an update for SINEC NMS and recommends to update to the latest version.
CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
CURL-CVE-2023-27538SSH connection too eager reuse still2023-03-20vendor · osvUS
libcurl would reuse a previously created connection even when an SSH related option had been changed that should have prohibited reuse. libcurl keeps previously used connections in a connection pool for subsequent transfers to reuse if one of them matches the setup. However, two SSH settings were left out from the configuration match checks, making them match too easily.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund siemens_psirt cisa_csaf_ot certfr osv NVD CVE.org MITRE

published 2023-03-30modified 2026-10-14

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references (27)

External citations — patches, advisories, analysis.

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