Description
In Libgcrypt before 1.7.7, an attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easily recover the long-term secret key. 1.7.7 makes a cipher/ecc-eddsa.c change to store this session key in secure memory, to ensure that constant-time point operations are used in the MPI library.
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 | 1.7.6-2 | — |
| Debian 13 | libgcrypt20 | 1.7.6-2 | — |
| Debian 12 | libgcrypt20 | 1.7.6-2 | — |
| Debian 8 | libgcrypt20 | 1.6.3-2+deb8u3 | DSA-3880-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | libgcrypt20 | 1.6.5-2ubuntu0.3 | USN-3347-1 |
| Ubuntu 14.04 LTS | libgcrypt11 | 1.5.3-2ubuntu4.5 | USN-3347-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | libgcrypt | 1.6.1-16.39.1 | SUSE-SU-2017:1608-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP2 | libgcrypt | 1.6.1-16.39.1 | SUSE-SU-2017:1608-1 |
Advisories 3
- USN-3347-1 libgcrypt11, libgcrypt20 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-3880-1 libgcrypt20 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2017:1608-1 Security update for libgcrypt SUSE / openSUSE Security Updates · Feb 4, 2026
References
- http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
- https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.html
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=5a22de904a0a366ae79f03ff1e13a1232a89e26b
- DSA-3880 vendor-advisory
- 99046 vdb-entry
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=f9494b3f258e01b6af8bd3941ce436bcc00afc56
- https://bugzilla.suse.com/show_bug.cgi?id=1042326