synced 14 MIN AGO
01 Record

CVE-2021-33560

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

HighPUBLISHEDCNA: mitre
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
View raw JSON

02 Description

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

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
2.37% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 83.5% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-10-14.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2021-06-08 00:00Z5 YR AGO
Last updated
2026-10-14 11:39Z15 DAYS AGO
Reserved
2021-05-24
Assigning CNA
mitre
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weaknesses
  • CWE-325Missing Cryptographic StepBase
  • CWE-203Observable DiscrepancyBase
Data version
5.2
Document digest
f5a1e2a69509a204e9452d6385bfb30d43104e2fe5404e93bf727fe2026fece0

05 Affected products

VendorProductVersionsPlatforms
debiandebian_linuxNot specified—
fedoraprojectfedoraNot specified—
gnupglibgcryptNot specified—
oraclecommunications_cloud_native_core_binding_support_functionNot specified—
oraclecommunications_cloud_native_core_network_function_cloud_native_environmentNot specified—
oraclecommunications_cloud_native_core_network_repository_functionNot specified—
oraclecommunications_cloud_native_core_network_slice_selection_functionNot specified—
oraclecommunications_cloud_native_core_service_communication_proxyNot specified—
redhatenterprise_linuxNot specified—

06 References

07 Fixed in

AlmaLinux 8

  • libgcrypt
    Fixed in 1.8.5-6.el8
  • libgcrypt-devel
    Fixed in 1.8.5-6.el8

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Arch Linux

  • lib32-libgcrypt
    Fixed in 1.9.3-1
  • libgcrypt
    Fixed in 1.9.3-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

CloudLinux 8

  • libgcrypt
    Fixed in 1.8.5-6.el8
  • libgcrypt-devel
    Fixed in 1.8.5-6.el8

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • libgcrypt20
    Fixed in 1.9.4-2

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • libgcrypt20
    Fixed in 1.9.4-2

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • libgcrypt20
    Fixed in 1.9.4-2

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • libgcrypt20
    Fixed in 1.8.1-4ubuntu1.3

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • libgcrypt20
    Fixed in 1.8.5-5ubuntu1.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • libgcrypt20
    Fixed in 1.8.7-5ubuntu2

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 16.04 LTS

  • libgcrypt20
    Fixed in 1.6.5-2ubuntu0.6+esm1
    Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS-updates 18.04 LTS

  • libgcrypt20
    Fixed in 1.8.1-4ubuntu1.fips.3
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS-updates 20.04 LTS

  • libgcrypt20
    Fixed in 1.8.5-5ubuntu1.fips.1.1
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS 18.04 LTS

  • libgcrypt20
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro FIPS 20.04 LTS

  • libgcrypt20
    Fixed in 1.8.5-5ubuntu1.fips.1.1
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.