Evidence used
- No CISA KEV confirmation is currently recorded.
- A structured source references public exploit or proof-of-concept material.
- EPSS is 1.99% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2023
CVE-2023-27533High confidence
n/a https://github.com/curl/curl — Failure to Sanitize Special Elements into a Different Plane (Special Element Injection)
Unknown · https://github.com/curl/curl
Official source article: Siemens SSA-398330 ↗. Check the applicable product and release in the original source.
8.8HighCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productHigh 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.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Critical, raised one band.upgradedsince 13 Feb 2026
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 Unknown https://github.com/curl/curl 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.
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
- Siemens ProductCERT: 1 affected or under-investigation product state without a fixed product state in the same current advisory
Distribution package intelligence
7 package statesRelease-specific package status
Alpine, Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
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 | curl | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 8.0.0-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Alpine v3.22v3.22 · main | curl | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 8.0.0-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Alpine v3.21v3.21 · main | curl | Vendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected. | 8.0.0-r0 | Alpine Security Database ↗Source updated 3 Oct 2026 |
| Debian trixietrixie · source | curl | Vendor fix publishedDebian records a fixed source-package version for this release. | 7.88.1-7 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian bookwormbookworm · source | curl | Vendor fix publishedDebian records a fixed source-package version for this release. | 7.88.1-7 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian forkyforky · source | curl | Vendor fix publishedDebian records a fixed source-package version for this release. | 7.88.1-7 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
| Debian sidsid · source | curl | Vendor fix publishedDebian records a fixed source-package version for this release. | 7.88.1-7 | Debian Security Tracker ↗Source updated 6 Oct 2026 |
Direct vendor intelligence
3 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2023-27533 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitycurl: TELNET option IAC injection
The vendor explicitly identifies these products or versions as containing the fix.
- jbcs-httpd24-curl-0:8.0.1-1.el7jbcs.src as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-curl-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-curl-debuginfo-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-libcurl-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-libcurl-devel-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-curl-0:8.0.1-1.el8jbcs.src as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-curl-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-curl-debuginfo-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-libcurl-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-libcurl-debuginfo-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-libcurl-devel-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- curl-debuginfo-0:7.76.1-26.el9.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- Summary
- A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
- Remediation
- For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Applications using the APR libraries, such as httpd, must be restarted for this update to take effect. After installing the updated packages, the httpd daemon will be restarted automatically.
SSA-398330 · CSAF 2.0 · revision 18 · interimSiemens ProductCERTSSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5
The vendor explicitly identifies these products as affected by this CVE.
- SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)
- SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)
- SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)
- SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)
- SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)
- Summary
- A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
- Remediation
- Update to V3.1.5 or later version
SSA-943925 · CSAF 2.0 · revision 2 · interimSiemens ProductCERTSSA-943925: Multiple Vulnerabilities in SINEC NMS before V2.0 SP1
The vendor explicitly identifies these products as affected by this CVE.
- SINEC NMS
- Summary
- A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
- Remediation
- Update to V2.0 SP1 or later version
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 product01
What, why and how
A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
What
A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
Why
The product does not adequately filter user-controlled input for special elements with control implications.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.
What
A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
Why
The product does not adequately filter user-controlled input for special elements with control implications.
How
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 Reference recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.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 → Failure to Sanitize Special Elements into a Different Plane (Special Element Injection) → execute code or commands in the affected security context
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- Required interaction required
- 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-75 ↗
CWE-75: Failure to Sanitize Special Elements into a Different Plane (Special Element Injection). The product does not adequately filter user-controlled input for special elements with control implications.
- 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:R/S:U/C:H/I:H/A:HCommon 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.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
03
Patch and workaround
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. - Fix availability varies by product
- Fixed
- jbcs-httpd24-curl-0:8.0.1-1.el7jbcs.src as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-curl-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-curl-debuginfo-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-libcurl-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-libcurl-devel-0:8.0.1-1.el7jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 7 Server
- jbcs-httpd24-curl-0:8.0.1-1.el8jbcs.src as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-curl-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-curl-debuginfo-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-libcurl-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-libcurl-debuginfo-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- jbcs-httpd24-libcurl-devel-0:8.0.1-1.el8jbcs.x86_64 as a component of Red Hat JBoss Core Services on RHEL 8
- curl-debuginfo-0:7.76.1-26.el9.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debuginfo-0:7.76.1-26.el9.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debuginfo-0:7.76.1-26.el9.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debuginfo-0:7.76.1-26.el9.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debuginfo-0:7.76.1-26.el9.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debugsource-0:7.76.1-26.el9.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debugsource-0:7.76.1-26.el9.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debugsource-0:7.76.1-26.el9.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debugsource-0:7.76.1-26.el9.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-debugsource-0:7.76.1-26.el9.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-minimal-debuginfo-0:7.76.1-26.el9.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-minimal-debuginfo-0:7.76.1-26.el9.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-minimal-debuginfo-0:7.76.1-26.el9.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-minimal-debuginfo-0:7.76.1-26.el9.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
- curl-minimal-debuginfo-0:7.76.1-26.el9.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- libcurl-debuginfo-0:7.76.1-26.el9.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- libcurl-debuginfo-0:7.76.1-26.el9.i686 as a component of Red Hat Enterprise Linux AppStream (v. 9)
- libcurl-debuginfo-0:7.76.1-26.el9.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 9)
- libcurl-debuginfo-0:7.76.1-26.el9.s390x as a component of Red Hat Enterprise Linux AppStream (v. 9)
- and 55 more
- Action
- 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 30 Mar 2023 · Last source change 13 Feb 2026, 20:09 UTC · CWE-75 · Failure to Sanitize Special Elements into a Different Plane (Special Element Injection)
CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2023-31288
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment
Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.
Material change intelligence
View recent updates ↗What changed after publication
- Affected versionsThe structured affected or fixed version information changed.Siemens ProductCERT ↗
- Before
- Fixed in 8.0.0 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
- After
- Fixed in 8.0.0 · Fixed: Update to V3.1.5 or later version
- Remediation statusRemediation status changed from Awaiting fix to Patch available.Siemens ProductCERT ↗
- Before
- Awaiting fix
- After
- Patch available
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.