CVE-2017-9526

Publication date 10 June 2017

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libgcrypt11	19.04 disco	Not in release
	18.10 cosmic	Not in release
	18.04 LTS bionic	Not in release
	17.10 artful	Not in release
	17.04 zesty	Not in release
	16.10 yakkety	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not affected
libgcrypt20	19.04 disco	Not affected
	18.10 cosmic	Not affected
	18.04 LTS bionic	Not affected
	17.10 artful	Not affected
	17.04 zesty	Fixed 1.7.6-1ubuntu0.1
	16.10 yakkety	Fixed 1.7.2-2ubuntu1.1
	16.04 LTS xenial	Fixed 1.6.5-2ubuntu0.3
	14.04 LTS trusty	Not in release

Notes

tyhicks

EdDSA support was added in 1.6.0

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libgcrypt20	Upstream: https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=f9494b3f258e01b6af8bd3941ce436bcc00afc56 Upstream: https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=91456759b887e153c4d4ce19538d478df260cab2

Severity score breakdown

Parameter	Value
Base score	5.9 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	None
Availability impact	None
Vector	CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N