What’s Vulnerable › Vulnerabilities

CVE-2017-7526

• Severity: medium (CVSS 6.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-07-26 · updated 2026-06-17
• Weakness: CWE-200

Description

libgcrypt before version 1.7.8 is vulnerable to a cache side-channel attack resulting into a complete break of RSA-1024 while using the left-to-right method for computing the sliding-window expansion. The same attack is believed to work on RSA-2048 with moderately more computation. This side-channel requires that attacker can run arbitrary software on the hardware where the private RSA key is used.

Affected products

• Canonical Ubuntu Linux: 12.04, 14.04, 16.04
• Debian Linux: 8.0, 9.0
• gnupg Libgcrypt: before 1.7.8 — fixed in 1.7.8

How to fix

Upgrade to a fixed version: gnupg Libgcrypt 1.7.8. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/99338
• http://www.securitytracker.com/id/1038915
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7526
• https://eprint.iacr.org/2017/627
• https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=78130828e9a140a9de4dafadbc844dbb64cb709a
• https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=8725c99ffa41778f382ca97233183bcd687bb0ce
• https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=e6a3dc9900433bbc8ad362a595a3837318c28fa9
• https://lists.gnupg.org/pipermail/gnupg-announce/2017q2/000408.html
• https://usn.ubuntu.com/3733-1/
• https://usn.ubuntu.com/3733-2/
• https://www.debian.org/security/2017/dsa-3901
• https://www.debian.org/security/2017/dsa-3960

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