CVE-2021-34798

mediumpriority · attend · 53EPSS 0.645 · 99 %ileDEEURUUS

grimoire priorityP1 · Urgent

Exploitable?

—

no known exploitation

Likely / severe?

64.5% (99th) EPSS

CVSS 5 · medium

Is it mine?

77 products

Check your exposure

Who says so?

8 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-22

Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.

remediations

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

A vendor fix is available.

FixedSINEC NMSsiemens_psirt
Update to V1.0.3 or later version
https://support.industry.siemens.com/cs/ww/en/view/109813788/
FixedSINEMA Remote Connect Serversiemens_psirt
Update to V3.1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109811169/
FixedCisco Firepower Extensible Operating System (FXOS)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com
FixedSINEC NMScisa_csaf_ot
Update to V1.0.3 or later version
https://support.industry.siemens.com/cs/ww/en/view/109813788/
FixedSINEMA Remote Connect Servercisa_csaf_ot
Update to V3.1 or later version
https://support.industry.siemens.com/cs/ww/en/view/109811169/
MitigationRUGGEDCOM NMSsiemens_psirt
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationSINEC NMSsiemens_psirt
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationSINEMA Remote Connect Serversiemens_psirt
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationSINEMA Server V14siemens_psirt
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationMELSOFT iQ AppPortal (SW1DND-IQAPL-M)cisa_csaf_ot
Install an antivirus software in the personal computer that runs this product.
MitigationRUGGEDCOM NMScisa_csaf_ot
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationSINEC NMScisa_csaf_ot
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationSINEMA Remote Connect Servercisa_csaf_ot
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
MitigationSINEMA Server V14cisa_csaf_ot
Restrict access to the affected systems, especially to port 443/tcp, to trusted IP addresses only
WorkaroundCisco Firepower Extensible Operating System (FXOS)cisco_csaf
Any workarounds will be documented in the product-specific Cisco bugs, which are identified in the Vulnerable Products ["#vp"] section of this advisory.
No fix plannedRUGGEDCOM NMSsiemens_psirt
Currently no fix is planned
No fix plannedSINEMA Server V14siemens_psirt
Currently no fix is planned
No fix plannedRUGGEDCOM NMScisa_csaf_ot
Currently no fix is planned
No fix plannedSINEMA Server V14cisa_csaf_ot
Currently no fix is planned

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

v3.07.5highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · CISA US

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

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Hsecondary · CVSS-BT (t0sche)

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

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

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

weaknesses

The CWE weakness classes this flaw belongs to.

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

affected products (77)

Products and version ranges known to be affected.

Juniper EX Seriesall versionscert_bundDEcpe:/h:juniper:ex:-
Juniper EX Series 4100all versionscert_bundDEcpe:/h:juniper:ex:4100
Juniper EX Series 4400all versionscert_bundDEcpe:/h:juniper:ex:4400
Juniper EX Series 4600all versionscert_bundDEcpe:/h:juniper:ex:ex4600
Juniper EX Series EX9200all versionscert_bundDEcpe:/h:juniper:ex:ex9200
Juniper JUNOSall versionscert_bundDEcpe:/o:juniper:junos:-
Juniper JUNOS ACX7024all versionscert_bundDEcpe:/o:juniper:junos:acx7024
Juniper JUNOS ACX7100-32Call versionscert_bundDEcpe:/o:juniper:junos:acx7100-32c
Juniper JUNOS ACX7100-48Lall versionscert_bundDEcpe:/o:juniper:junos:acx7100-48l
Juniper JUNOS Evolvedall versionscert_bundDEcpe:/o:juniper:junos:evolved
Juniper JUNOS PTX Seriesall versionscert_bundDEcpe:/o:juniper:junos:ptx_series
Juniper Junos Space <24.1R2all versionscert_bundDE
Juniper MX Seriesall versionscert_bundDEcpe:/h:juniper:mx:-
Juniper QFX Series 5000all versionscert_bundDEcpe:/h:juniper:qfx:qfx5000
Juniper SRX Seriesall versionscert_bundDEcpe:/h:juniper:srx_service_gateways:-
Juniper Junos Space< 24.1R2cert_bundDE
RUGGEDCOM NMSall versionscisa_csaf_otUS
SINEC NMSall versionscisa_csaf_otUS
SINEMA Remote Connect Serverall versionscisa_csaf_otUS
SINEMA Server V14all versionscisa_csaf_otUS

showing 20 of 77

advisories (9)

Vendor and ecosystem advisories describing this.

SSA-685781SSA-685781: Multiple Vulnerabilities in Apache HTTP Server Affecting Siemens Products2022-06-14csaf · siemens_psirtDE
Multiple vulnerabilities were identified in the Apache HTTP Server software. These include NULL Pointer Dereferencing, Out-of-bounds Write and Server-Side Request Forgery related vulnerabilities. Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends specific countermeasures for products where updates are not, or not yet available.
WID-SEC-W-2022-0724Apache HTTP Server: Mehrere SchwachstellenDeutsch2021-09-16csaf · cert_bundDE
Ein entfernter Angreifer kann mehrere Schwachstellen in Apache HTTP Server ausnutzen, um Sicherheitsvorkehrungen zu umgehen, vertrauliche Informationen offenzulegen und einen Denial of Service Zustand herzustellen.
WID-SEC-W-2023-1016Oracle Fusion Middleware: Mehrere SchwachstellenDeutsch2023-04-18csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Oracle Fusion Middleware ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
WID-SEC-W-2024-0064Juniper Produkte: Mehrere SchwachstellenDeutsch2024-01-10csaf · cert_bundDE
Ein Angreifer aus dem angrenzenden Netzwerk oder ein entfernter, anonymer, authentisierter, lokaler oder physischer Angreifer kann mehrere Schwachstellen in Juniper JUNOS, Juniper JUNOS Evolved, Juniper SRX Series, Juniper EX Series, Juniper QFX Series, Juniper ACX Series, Juniper PTX Series und Juniper MX Series ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand herbeizuführen und seine Berechtigungen zu erweitern.
WID-SEC-W-2024-1591Juniper JUNOS: Mehrere SchwachstellenDeutsch2024-07-10csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Juniper JUNOS ausnutzen, um einen Denial of Service zu verursachen, Informationen offenzulegen, Privilegien zu erweitern und Sicherheitsmechanismen inklusive zu umgehen.
cisco-sa-apache-httpd-2.4.49-VWL69sWQMultiple Vulnerabilities in Apache HTTP Server Affecting Cisco Products: November 20212021-11-24csaf · cisco_csafUS
On September 16, 2021, the Apache Software Foundation disclosed five vulnerabilities affecting the Apache HTTP Server (httpd) 2.4.48 and earlier releases. For a description of these vulnerabilities, see the Apache HTTP Server 2.4.49 section ["https://httpd.apache.org/security/vulnerabilities_24.html#2.4.49"] of the Apache HTTP Server 2.4 vulnerabilities webpage. This advisory will be updated as additional information becomes available.
ICSA-22-132-02Mitsubishi Electric MELSOFT iQ AppPortal2022-05-12icsa · cisa_csaf_otUS
Successful exploitation of these vulnerabilities could result in a denial-of-service condition, malicious program execution, information disclosure, information tampering, or authentication bypass.
ICSA-22-167-06Siemens Apache HTTP Server2022-06-14icsa · cisa_csaf_otUS
Multiple vulnerabilities were identified in the Apache HTTP Server software. These include NULL Pointer Dereferencing, Out-of-bounds Write and Server-Side Request Forgery related vulnerabilities. Siemens has released updates for several affected products and recommends to update to the latest versions. Siemens recommends specific countermeasures for products where updates are not, or not yet available.
BIT-apache-2021-34798NULL pointer dereference in httpd core2024-03-06vendor · osvUS
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.

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 siemens_psirt cisco_csaf osv NVD CVE.org MITRE

published 2021-09-16modified 2026-06-17

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+8748 more

references (97)

External citations — patches, advisories, analysis.

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