Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: Improper Restriction of XML External Entity Reference
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
Official source article: Siemens SSA-398330 ↗. Check the applicable product and release in the original source.
7.5HighCVSS 3.1
Recommended action
Patch only the product branches with a verified fix
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 6 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 30 May 2025
Evidence used
No CISA KEV confirmation is currently recorded.
A structured source references public exploit or proof-of-concept material.
The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
EPSS is 7.11% for the current model date.
Compensating controls
Validate the affected product branch and deploy the verified fixed release.
Restrict the affected network interface to trusted sources where business-safe.
Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
Confirm that the asset runs Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP and falls inside the recorded affected range.
Verify the installed build against the product-specific fixed version after deployment.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Cross-source reconciliation
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 6 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Siemens ProductCERT: 5 affected or under-investigation product states without a fixed product state in the same current advisory
Debian Security Tracker: 1 affected package state with no published fix
Distribution package intelligence
Release-specific package status
Alpine, Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
13 package states
Package result overrides the generic status
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Distribution release
Source package
Vendor state
Fixed version
Evidence
Alpine v3.23v3.23 · main
expat
Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.
Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
The vendor explicitly identifies these products as affected by this CVE.
expat as component of HPE Helion OpenStack 8
libexpat1 as component of HPE Helion OpenStack 8
libexpat1-32bit as component of HPE Helion OpenStack 8
expat as component of SUSE Enterprise Storage 7
expat as component of SUSE Linux Enterprise High Performance Computing 12 SP2
libexpat1 as component of SUSE Linux Enterprise High Performance Computing 12 SP2
libexpat1-32bit as component of SUSE Linux Enterprise High Performance Computing 12 SP2
expat as component of SUSE Linux Enterprise High Performance Computing 12 SP4
libexpat1 as component of SUSE Linux Enterprise High Performance Computing 12 SP4
libexpat1-32bit as component of SUSE Linux Enterprise High Performance Computing 12 SP4
expat as component of SUSE Linux Enterprise High Performance Computing 12 SP5
libexpat1 as component of SUSE Linux Enterprise High Performance Computing 12 SP5
Summary
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Remediation
Update to V3.1.5 or later version
CVE-2018-20843 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityexpat: large number of colons in input makes parser consume high amount of resources, leading to DoSNo longer in the provider’s current catalogue
17 known affected
The vendor explicitly identifies these products as affected by this CVE.
expat.src as a component of Red Hat Enterprise Linux 5
xmlrpc-c.src as a component of Red Hat Enterprise Linux 5
compat-expat1 as a component of Red Hat Enterprise Linux 6
compat-expat1.src as a component of Red Hat Enterprise Linux 6
expat as a component of Red Hat Enterprise Linux 6
expat-devel as a component of Red Hat Enterprise Linux 6
expat.src as a component of Red Hat Enterprise Linux 6
httpd as a component of Red Hat JBoss Enterprise Application Platform 6
httpd-devel as a component of Red Hat JBoss Enterprise Application Platform 6
httpd-manual as a component of Red Hat JBoss Enterprise Application Platform 6
httpd-tools as a component of Red Hat JBoss Enterprise Application Platform 6
httpd.src as a component of Red Hat JBoss Enterprise Application Platform 6
Summary
It was discovered that the "setElementTypePrefix()" function incorrectly extracted XML namespace prefixes. By tricking an application into processing a specially crafted XML file, an attacker could cause unusually high consumption of memory resources and possibly lead to a denial of service.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2018-13383
No EUVD known-exploited evidence
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.5 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 6 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product
01
What, why and how
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
What
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Why
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
What
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Why
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
Likely attack path
a network path → Improper Restriction of XML External Entity Reference → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-611: Improper Restriction of XML External Entity Reference. The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
CVSS vector ?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2018-13383Official EUVD mapping
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Official EUVD record ↗BSI · German · WID-SEC-2025-0227IBM QRadar SIEM: Mehrere Schwachstellen
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um seine Privilegien zu erweitern, Administratorrechte zu erlangen, beliebigen Programmcode auszuführen, Informationen offenzulegen, Dateien zu manipulieren oder Sicherheitsvorkehrungen zu umgehen.
Official advisory ↗BSI · German · WID-SEC-2024-1735expat: Schwachstelle ermöglicht Denial of Service
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in expat ausnutzen, um einen Denial of Service Angriff durchzuführen.
In libexpat in Expat before 2.2.7, XML input including XML names that contain a large number of colons could make the XML parser consume a high amount of RAM and CPU resources while processing (enough to be usable for denial-of-service attacks).
Official advisory ↗CERT-FR · French · CERTFR-2023-AVI-1015Multiples vulnérabilités dans les produits Siemens
Official advisory ↗CERT-FR · French · CERTFR-2021-AVI-589Multiples vulnérabilités dans Juniper Junos Space Log Collector
couvertes dans Juniper Junos Space
Log Collector. Certaines d'entre elles permettent à un attaquant de
provoquer une exécution de code arbitraire à distance, un déni de
service à distance et une atteinte à l'intégrité des données.
Solution
Se référer au bulletin de sécurité de l'éditeur pour l'obtention des
correctifs (cf. section Documentation).
Documentation
Bulletin de sécurité Juniper JSA11209 du 02 août 2021
https://kb.juniper.net/InfoCenter/index?page=content&id=JSA11209
Référence CVE CVE-2017-12652
https://www.cve.org/CVERecord?id=CVE-2017-12652
Référence CVE CVE-2018-20836
https://www.cve.org/CVERecord?id=CVE-2018-20836
Référence CVE CVE-2018-20843
https://www.cve.org/CVERecord?id=CVE-2018-20843
Référence CVE CVE-2019-11068
https://www.cve.org/CVERecord?id=CVE-2019-11068
Référence CVE CVE-2019-11756
https://www.cve.org/CVERecord?id=CVE-2019-11756
Référence CVE CVE-2019-12450
https://www.cve.org/CVERecord?id=CVE-2019-12450
Référence CVE CVE-2019-12614
https://www.cve.org/CVERecord?id=CVE-2019-12614
Référence CVE CVE-2019-14866
https://www.cve.org/CVERecord?id=CVE-2019-14866
Référence CVE CVE-2019-15807
https://www.cve.org/CVERecord?id=CVE-2019-15807
Référence CVE CVE-2019-15917
https://www.cve.org/CVERecord?id=CVE-2019-15917
Référence CVE CVE-2019-16231
https://www.cve.org/CVERecord?id=
Official advisory ↗CERT-FR · French · CERTFR-2021-AVI-466Multiples vulnérabilités dans les produits Tenable
De multiples vulnérabilités ont été découvertes dans les produits
Tenable. Elles permettent à un attaquant de provoquer une élévation de
privilèges.
Official advisory ↗CERT-FR · French · CERTFR-2020-AVI-691Multiples vulnérabilités dans les produits Juniper
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04
Evidence and provenance
Published 24 Jun 2019 · Last source change 14 Oct 2026, 06:30 UTC · CWE-611 · Improper Restriction of XML External Entity Reference
CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-09-01
European sourceENISA EUVD · EUVD-2018-13383
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
CWE sourceCISA ADP
NVD statusNVD modified after enrichment
Core structured fields are present and their contributing authorities are shown above.
Affected versionsThe structured affected or fixed version information changed.
Before
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: V3.1.0 < V3.1.5; SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5 · Fixed: Update to V3.1.5 or later version
After
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: V3.1.0 < V3.1.5; SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Affected versionsThe structured affected or fixed version information changed.
Before
n/a · Fixed: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
After
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: V3.1.0 < V3.1.5; SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Affected versionsThe structured affected or fixed version information changed.
Before
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: V3.1.0 < V3.1.5; SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5; SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: V3.1.0 < V3.1.5; SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: V3.1.0 < V3.1.5 · Fixed: Update to V3.1.5 or later version
Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2018-20843 to advisory no longer present in the provider's current catalogue.
Before
remediation: access.redhat.com/CVE-2018-20843
After
advisory no longer present in the provider's current catalogue
Affected versionsThe structured affected or fixed version information changed.
Before
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
After
n/a · Fixed: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Affected versionsThe structured affected or fixed version information changed.
Before
n/a · Fixed: No fixed version is explicitly recorded in the structured CVE data.
After
n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.