CVE-2021-33560

mediumpriority · track · 41OT risk · elevatedEPSS 0.024 · 84 %ileexploit · PoCDEEURUUS
grimoire priorityP1 · Urgent
Exploitable?
Public exploit
1 exploit · PoC
Likely / severe?
2.37% (84th) EPSS
CVSS 5 · medium
Is it mine?
70 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cisa_csaf_ot

EPSS · scored 2026-10-27

Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP.

01

remediations

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

A vendor fix is available.

02

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:P/I:N/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:Csecondary · CISA US
v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · FSTEC (BDU) RU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · ENISA EU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondaryexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:Csecondary · Siemens ProductCERT DE
v3.17.1highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Psecondary · CVSS-BT (t0sche)
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · Red Hat Product Security US
03

ssvc

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

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-203USprimaryCWE-203USCWE-203USCWE-203USCWE-325USCWE-327US
05

exploits (1)

Public proof-of-concept and weaponised exploit code.

06

affected products (70)

Products and version ranges known to be affected.

showing 20 of 70
07

advisories (3)

Vendor and ecosystem advisories describing this.

  • RHSA-2021:4409Red Hat Security Advisory: libgcrypt security and bug fix update2021-11-09csaf · redhat_csafUS

    An update for libgcrypt is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

  • 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).

  • 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).

08

also known as (4)

Other names and identifiers for this entity.

09

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisa_csaf_otredhat_csafsiemens_psirtNVDCVE.orgMITRE
published 2021-06-08modified 2026-06-17
11

references (68)

External citations — patches, advisories, analysis.

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