Medium 5.9Published Sep 29, 2021

CVE-2021-22947When curl >= 7.20.0 and <= 7.78.0 connects to an IMAP or POP3 server to retrieve data using STARTTLS to upgrade to TLS security, the server can respond and send back multiple responses at once that c…

Updated under an hour ago (2026-10-19 05:50 UTC)

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It affects Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP and 28 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP

Exploited in the last 30 days

When curl >= 7.20.0 and <= 7.78.0 connects to an IMAP or POP3 server to retrieve data using STARTTLS to upgrade to TLS security, the server can respond and send back multiple responses at once that curl caches. curl would then upgrade to TLS but not flush the in-queue of cached responses but instead continue using and trustingthe responses it got *before* the TLS handshake as if they were authenticated.Using this flaw, it allows a Man-In-The-Middle attacker to first inject the fake responses, then pass-through the TLS traffic from the legitimate server and trick curl into sending data back to the user thinking the attacker's injected data comes from the TLS-protected server.

CVSS: 5.9 MEDIUM (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-310
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: hackerone
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.0 before V3.1.5	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.0 before V3.1.5	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.0 before V3.1.5	CISA ADP
haxx curl haxx:curl	from 7.20.0 before 7.79.0	NVD
fedoraproject fedora fedoraproject:fedora	33; 35	NVD
debian debian_linux debian:debian_linux	9.0; 10.0; 11.0	NVD
netapp cloud_backup netapp:cloud_backup	all versions	NVD
netapp clustered_data_ontap netapp:clustered_data_ontap	all versions	NVD
netapp h300s_firmware netapp:h300s_firmware	all versions	NVD
netapp h500s_firmware netapp:h500s_firmware	all versions	NVD
netapp h700s_firmware netapp:h700s_firmware	all versions	NVD
netapp h300e_firmware netapp:h300e_firmware	all versions	NVD
netapp h500e_firmware netapp:h500e_firmware	all versions	NVD
netapp h700e_firmware netapp:h700e_firmware	all versions	NVD
netapp h410s_firmware netapp:h410s_firmware	all versions	NVD
netapp solidfire_baseboard_management_controller_firmware netapp:solidfire_baseboard_management_controller_firmware	all versions	NVD
oracle communications_cloud_native_core_binding_support_function oracle:communications_cloud_native_core_binding_support_function	1.11.0; 22.1.3	NVD
oracle communications_cloud_native_core_network_function_cloud_native_environment oracle:communications_cloud_native_core_network_function_cloud_native_environment	1.10.0	NVD
oracle communications_cloud_native_core_network_repository_function oracle:communications_cloud_native_core_network_repository_function	1.15.0; 1.15.1; 22.1.2; 22.2.0	NVD
oracle communications_cloud_native_core_network_slice_selection_function oracle:communications_cloud_native_core_network_slice_selection_function	1.8.0	NVD
oracle communications_cloud_native_core_service_communication_proxy oracle:communications_cloud_native_core_service_communication_proxy	1.15.0	NVD
oracle mysql_server oracle:mysql_server	from 5.7.0 through 5.7.35; from 8.0.0 through 8.0.26	NVD
oracle peoplesoft_enterprise_peopletools oracle:peoplesoft_enterprise_peopletools	8.57; 8.58; 8.59	NVD
siemens sinec_infrastructure_network_services siemens:sinec_infrastructure_network_services	before 1.0.1.1	NVD
apple macos apple:macos	before 12.3	NVD
oracle commerce_guided_search oracle:commerce_guided_search	11.3.2	NVD
oracle communications_cloud_native_core_console oracle:communications_cloud_native_core_console	22.2.0	NVD
oracle communications_cloud_native_core_security_edge_protection_proxy oracle:communications_cloud_native_core_security_edge_protection_proxy	22.1.1	NVD
splunk universal_forwarder splunk:universal_forwarder	from 8.2.0 before 8.2.12; from 9.0.0 before 9.0.6; 9.1.0	NVD

References

https://hackerone.com/reports/1334763exploit, issue-tracking, third-party-advisory
https://lists.debian.org/debian-lts-announce/2021/09/msg00022.htmlmailing-list, third-party-advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RWLEC6YVEM2HWUBX67SDGPSY4CQB72OE/vendor-advisory, mailing-list, third-party-advisory
https://www.oracle.com/security-alerts/cpuoct2021.htmlpatch, third-party-advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/APOAK4X73EJTAPTSVT7IRVDMUWVXNWGD/vendor-advisory, mailing-list, third-party-advisory
https://www.oracle.com/security-alerts/cpujan2022.htmlpatch, third-party-advisory
https://security.netapp.com/advisory/ntap-20211029-0003/third-party-advisory
http://seclists.org/fulldisclosure/2022/Mar/29mailing-list, third-party-advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlpatch, third-party-advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdfpatch, third-party-advisory
https://support.apple.com/kb/HT213183release-notes, third-party-advisory
https://www.oracle.com/security-alerts/cpujul2022.htmlpatch, third-party-advisory
https://www.debian.org/security/2022/dsa-5197vendor-advisory, third-party-advisory
https://lists.debian.org/debian-lts-announce/2022/08/msg00017.htmlmailing-list, third-party-advisory
https://security.gentoo.org/glsa/202212-01vendor-advisory, third-party-advisory
https://cert-portal.siemens.com/productcert/html/ssa-389290.html
https://cert-portal.siemens.com/productcert/html/ssa-398330.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.