CVE-2021-28831

mediumpriority · track · 31EPSS 0.027 · 86 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.72% (86th) EPSS

CVSS 5 · medium

Is it mine?

34 products

Check your exposure

Who says so?

6 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

decompress_gunzip.c in BusyBox through 1.32.1 mishandles the error bit on the huft_build result pointer, with a resultant invalid free or segmentation fault, via malformed gzip data.

remediations

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

A vendor fix is available.

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/
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

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

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

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · cve@mitre.org 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 · 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.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-755USprimaryCWE-755USCWE-755USCWE-755US

affected products (34)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
Hirschmann BAT-C2 <9.13.1.0R2all versionscert_bundDE
Hirschmann owl <6.3.7all versionscert_bundDE
NetApp AFF Baseboard Management Controllerall versionscert_bundDEcpe:/h:netapp:aff:::baseboard_management_controller
NetApp FAS Baseboard Management Controllerall versionscert_bundDEcpe:/h:netapp:fas:baseboard_management_controller
Open Source Arch Linuxall versionscert_bundDEcpe:/o:archlinux:archlinux:-
Open Source BusyBox <=1.32.1all versionscert_bundDE
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
Ubuntu Linuxall versionscert_bundDEcpe:/o:canonical:ubuntu_linux:-
Hirschmann BAT-C2< 9.13.1.0R2cert_bundDE
Hirschmann owl< 6.3.7cert_bundDE
Open Source BusyBox≤ 1.32.1cert_bundDE
SIMATIC S7-1500 TM MFP - BIOSall versionscisa_csaf_otUS
Siemens SIMATIC S7-1500 TM MFP - BIOS< V1.3.0cisa_csaf_otUS
n/a n/a≤ n/aenisa_euvdEU
Fedora Project Fedora≤ 34fstec_bduRU
Fedora Project Fedora≤ 32fstec_bduRU
Fedora Project Fedora≤ 33fstec_bduRU
АО «Концерн ВНИИНС» ОС ОН «Стрелец»≤ 16.01.2023fstec_bduRU

showing 20 of 34

advisories (4)

Vendor and ecosystem advisories describing this.

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-2022-2029BusyBox: Schwachstelle ermöglicht Denial of ServiceDeutsch2021-03-25csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann eine Schwachstelle in BusyBox ausnutzen, um einen Denial of Service Angriff durchzuführen.
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.
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.

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 NVD CVE.org MITRE

published 2021-03-19modified 2026-06-17

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+700 more

references (38)

External citations — patches, advisories, analysis.

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