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 appropriately. This, for example, affects use of ElGamal in OpenPGP.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libgcrypt20 | 1.9.4-2 | — |
| Debian 13 | libgcrypt20 | 1.9.4-2 | — |
| Debian 12 | libgcrypt20 | 1.9.4-2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | libgcrypt20 | 1.8.7-5ubuntu2 | — |
| Ubuntu 20.04 LTS | libgcrypt20 | 1.8.5-5ubuntu1.1 | USN-5080-1 |
| Ubuntu 18.04 LTS | libgcrypt20 | 1.8.1-4ubuntu1.3 | USN-5080-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro FIPS 20.04 LTS | libgcrypt20 | 1.8.5-5ubuntu1.fips.1.1 | — |
| Ubuntu Pro FIPS 18.04 LTS | libgcrypt20 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | libgcrypt20 | 1.8.5-5ubuntu1.fips.1.1 | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | libgcrypt20 | 1.8.1-4ubuntu1.fips.3 | — |
| Ubuntu Pro 16.04 LTS | libgcrypt20 | 1.6.5-2ubuntu0.6+esm1 | USN-5080-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | libgcrypt +1 | 1.8.5-6.el8 | RHSA-2021:4409 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | libgcrypt +1 | 1.8.5-6.el8 | ALSA-2021:4409 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | libgcrypt | 1.8.5-6.el8 | RLSA-2021:4409 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SLES 15 SP2 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SLES 15 SP1 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SLES 15 | libgcrypt | 1.8.2-6.52.1 | SUSE-SU-2021:2155-1 |
| SLES 12 SP5 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
Show 22 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SLES 12 SP3 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SLES 12 SP2 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SLES 11 SP4 | libgcrypt | 1.5.0-0.26.6.1 | SUSE-SU-2021:14751-1 |
| SLES for SAP 15 SP1 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SLES for SAP 15 | libgcrypt | 1.8.2-6.52.1 | SUSE-SU-2021:2155-1 |
| SLES for SAP 12 SP5 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SLES for SAP 12 SP4 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SLES for SAP 12 SP3 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SLE Micro 5.0 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SLE HPC 15 SP1 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SLE HPC 15 | libgcrypt | 1.8.2-6.52.1 | SUSE-SU-2021:2155-1 |
| SUSE OpenStack Cloud Crowbar 9 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SUSE OpenStack Cloud Crowbar 8 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SUSE OpenStack Cloud 9 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SUSE OpenStack Cloud 8 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SUSE Manager Server 4.0 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SUSE Manager Retail Branch Server 4.0 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SUSE Manager Proxy 4.0 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | libgcrypt | 1.5.0-0.26.6.1 | SUSE-SU-2021:14751-1 |
| SUSE HPE Helion OpenStack 8 | libgcrypt | 1.6.1-16.77.1 | SUSE-SU-2021:2156-1 |
| SUSE Enterprise Storage 6 | libgcrypt | 1.8.2-8.39.1 | SUSE-SU-2021:2157-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libgcrypt | 1.9.4-1.2 | openSUSE-SU-2024:10941-1 |
| openSUSE Leap 15.3 | libgcrypt | 1.8.2-8.39.1 | openSUSE-SU-2021:2157-1 |
| openSUSE Leap 15.2 | libgcrypt | 1.8.2-lp152.17.3.1 | openSUSE-SU-2021:0919-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.23 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.22 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.21 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.20 | libgcrypt | 1.9.4-r0 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.18 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.17 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.16 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.15 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.14 | libgcrypt | 1.9.4-r0 | — |
| Alpine v3.13 | libgcrypt | 1.8.8-r0 | — |
| Alpine v3.12 | libgcrypt | 1.8.8-r0 | — |
| Alpine v3.11 | libgcrypt | 1.8.8-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | libgcrypt +1 | 1.5.3-14.amzn2.0.3 | ALAS2-2022-1769 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | libgcrypt +1 | 1.8.5-6.el8 | ELSA-2022-9263, ELSA-2021-4409 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
GitHub 1 repository
-
IBM/PGP-client-checker-CVE-2021-33560 ★ 1 · Jul 16, 2021
Tool to check whether a PGP client is affected by CVE-2021-33560
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 17
- ALSA-2021:4409 Moderate: libgcrypt security and bug fix update AlmaLinux Security Advisories · Oct 29, 2026
- SSA-398330 SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5 Siemens ProductCERT · Oct 13, 2026
- USN-5080-2 libgcrypt20 vulnerabilities Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-5080-1 libgcrypt20 vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- RLSA-2021:4409 Moderate: libgcrypt security and bug fix update Rocky Linux Security Advisories · Feb 4, 2026
- SUSE-SU-2021:2156-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2155-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0919-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14751-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10941-1 libgcrypt-cavs-1.9.4-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:2157-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2157-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2021:4409 Red Hat Security Advisory: libgcrypt security and bug fix update Red Hat Security Advisories (RHSA) · Dec 4, 2025
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- ALAS2-2022-1769 Moderate: libgcrypt security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Apr 6, 2022
- ELSA-2022-9263 Moderate: libgcrypt security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Apr 6, 2022
- ELSA-2021-4409 Moderate: libgcrypt security and bug fix update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 16, 2021
References
- https://dev.gnupg.org/T5328
- [debian-lts-announce] 20210624 [SECURITY] [DLA 2691-1] libgcrypt20 security update mailing-list
- FEDORA-2021-24d4e06195 vendor-advisory
- FEDORA-2021-31fdc84207 vendor-advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://dev.gnupg.org/T5466
- https://dev.gnupg.org/T5305
- https://dev.gnupg.org/rCe8b7f10be275bcedb5fc05ed4837a89bfd605c61
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- GLSA-202210-13 vendor-advisory