CVE-2021-38604

mediumpriority · track · 31EPSS 0.037 · 90 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

3.72% (90th) EPSS

CVSS 5 · medium

Is it mine?

35 products

Check your exposure

Who says so?

7 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

In librt in the GNU C Library (aka glibc) through 2.34, sysdeps/unix/sysv/linux/mq_notify.c mishandles certain NOTIFY_REMOVED data, leading to a NULL pointer dereference. NOTE: this vulnerability was introduced as a side effect of the CVE-2021-33574 fix.

remediations

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

A vendor fix is available.

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/
FixedSIMATIC S7-1500 TM MFP - BIOSsiemens_psirt
Update to V1.3.0 or later version
https://support.industry.siemens.com/cs/ww/en/view/109945851/
FixedSIMATIC S7-1500 TM MFP - BIOScisa_csaf_ot
Update to V1.3.0 or later version
https://support.industry.siemens.com/cs/ww/en/view/109945851/
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/
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.
WorkaroundSIMATIC S7-1500 TM MFP - BIOSsiemens_psirt
Only build and run applications from trusted sources
WorkaroundSIMATIC S7-1500 TM MFP - BIOScisa_csaf_ot
Only build and run applications from trusted sources

cvss

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

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

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

v3.15.9mediumAV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondaryexploitability 3.9 · impact 3.6

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

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

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

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-476USprimaryCWE-476USCWE-476USCWE-476US

affected products (35)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)all versionscisa_csaf_otUS
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)all versionscisa_csaf_otUS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)all versionscisa_csaf_otUS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)all versionscisa_csaf_otUS
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)all versionscisa_csaf_otUS
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)≤ vers:intdot/>=3.1.0|<3.1.5cisa_csaf_otUS
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)≤ vers:intdot/>=3.1.0|<3.1.5cisa_csaf_otUS
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)≤ vers:intdot/>=3.1.0|<3.1.5cisa_csaf_otUS
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)≤ vers:intdot/>=3.1.0|<3.1.5cisa_csaf_otUS
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)≤ vers:intdot/>=3.1.0|<3.1.5cisa_csaf_otUS
n/a n/a≤ n/aenisa_euvdEU
The GNU Project glibc≤ 2.34fstec_bduRU
ООО «КНС ГРУПП» Татлин-Юнифайд≤ 3.2.1fstec_bduRU
fedoraproject fedora= 35nvdUScpe:2.3:o:fedoraproject:fedora:*:*:*:*:*:*:*:*
gnu glibc≤ 2.34nvdUScpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:*
oracle communications cloud native core binding support function= 22.1.3nvdUScpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:*:*:*:*:*:*:*:*
oracle communications cloud native core network function cloud native environment= 22.1.0nvdUScpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:*:*:*:*:*:*:*:*
oracle communications cloud native core network repository function= 22.1.2nvdUScpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:*:*:*:*:*:*:*:*
oracle communications cloud native core network repository function= 22.2.0nvdUScpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:*:*:*:*:*:*:*:*

showing 20 of 35

advisories (6)

Vendor and ecosystem advisories describing this.

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-831302SSA-831302: Vulnerabilities in the BIOS of the SIMATIC S7-1500 TM MFP before V1.3.02023-06-13csaf · siemens_psirtDE
Multiple vulnerabilities have been identified in the BIOS of the SIMATIC S7-1500 TM MFP before V1.3.0. Siemens has released a new version for SIMATIC S7-1500 TM MFP - BIOS and recommends to update to the latest version.
WID-SEC-W-2023-1432Siemens SIMATIC S7: Mehrere SchwachstellenDeutsch2023-06-12csaf · cert_bundDE
Ein Angreifer aus dem angrenzenden Netzwerk oder ein entfernter, anonymer, authentisierter, physischer oder lokaler Angreifer kann mehrere Schwachstellen in Siemens SIMATIC S7 ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand herbeizuführen, seine Privilegien zu erweitern und Daten zu manipulieren.
WID-SEC-W-2023-3051GNU libc: Schwachstelle ermöglicht nicht spezifizierten AngriffDeutsch2021-08-12csaf · cert_bundDE
Ein lokaler Angreifer kann eine Schwachstelle in GNU libc ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.
ICSA-23-166-10Siemens SIMATIC S7-1500 TM MFP BIOS2023-06-13icsa · cisa_csaf_otUS
Multiple vulnerabilities have been identified in the BIOS of the SIMATIC S7-1500 TM MFP before V1.3.0. Siemens has released a new version for SIMATIC S7-1500 TM MFP - BIOS and recommends to update to the latest version.
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).

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 cisa_csaf_ot nvd siemens_psirt NVD CVE.org MITRE

published 2021-08-12modified 2026-08-10

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references (27)

External citations — patches, advisories, analysis.

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