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Fencer Vulns
medium 5.9

CVE-2017-9526 json

In Libgcrypt before 1.7.7, an attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easi…

published 2017-06-11 9 y ago modified 2026-06-17 4 mo ago also EUVD-2017-18457

cvss
5.9
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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.

Patch / fix

  • libgcrypt20 Debian 14, Debian 13, Debian 12 1.7.6-2

debian advisories DEBIAN-CVE-2017-9526

  • libgcrypt20 Ubuntu 16.04 LTS 1.6.5-2ubuntu0.3

ubuntu advisories UBUNTU-CVE-2017-9526

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libgcrypt SLES for SAP 12 SP2, SLES for Raspberry Pi 12 SP2, SLES 12 SP2 +2 more 1.6.1-16.39.1

suse advisories SUSE-SU-2017:1608-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-9526 updated cvss 5.9

libgcrypt: Possible timing attack on EdDSA session key

  • Red Hat Enterprise Linux 5 libgcrypt Red Hat Enterprise Linux 6 libgcrypt Red Hat Enterprise Linux 7 libgcrypt Red Hat Enterprise Virtualization 3 mingw-virt-viewer, mingw32-virt-viewer, mingw64-virt-viewer
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.32% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.