CVE-2023-43809

Soft Serve Public Key Authentication Bypass Vulnerability when Keyboard-Interactive SSH Authentication is Enabled

Published Oct 4, 2023 CVSS 3.1 · 7.5 High EPSS 1.2% KEV · Not listed
Description
Soft Serve is a self-hostable Git server for the command line. Prior to version 0.6.2, a security vulnerability in Soft Serve could allow an unauthenticated, remote attacker to bypass public key authentication when keyboard-interactive SSH authentication is active, through the `allow-keyless` setting, and the public key requires additional client-side verification for example using FIDO2 or GPG. This is due to insufficient validation procedures of the public key step during SSH request handshake, granting unauthorized access if the keyboard-interaction mode is utilized. An attacker could exploit this vulnerability by presenting manipulated SSH requests using keyboard-interactive authentication mode. This could potentially result in unauthorized access to the Soft Serve. Users should upgrade to the latest Soft Serve version `v0.6.2` to receive the patch for this issue. To workaround this vulnerability without upgrading, users can temporarily disable Keyboard-Interactive SSH Authentication using the `allow-keyless` setting.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2023-2773 Soft Serve is a self-hostable Git server for the command line. Prior to version 0.6.2, a security vulnerability in Soft Serve could allow an unauthenticated, remote attacker to bypass public key authentication when keyboard-interactive SSH authentication is active, through the `allow-keyless` setting, and the public key requires additional client-side verification for example using FIDO2 or GPG. This is due to insufficient validation procedures of the public key step during SSH request handshake, granting unauthorized access if the keyboard-interaction mode is utilized. An attacker could exploit this vulnerability by presenting manipulated SSH requests using keyboard-interactive authentication mode. This could potentially result in unauthorized access to the Soft Serve. Users should upgrade to the latest Soft Serve version `v0.6.2` to receive the patch for this issue. To workaround this vulnerability without upgrading, users can temporarily disable Keyboard-Interactive SSH Authentication using the `allow-keyless` setting.
Github GHSA Github GHSA GHSA-mc97-99j4-vm2v Soft Serve Public Key Authentication Bypass Vulnerability when Keyboard-Interactive SSH Authentication is Enabled
History
Type Values Removed Values Added
First Time appeared Charmbracelet
Charmbracelet soft-serve
CPEs cpe:2.3:a:charmbracelet:soft-serve:*:*:*:*:*:*:*:*
Vendors & Products Charmbracelet
Charmbracelet soft-serve
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 20, 2024, 2:51 PM
Reserved
Sep 22, 2023, 2:51 PM
Status
Modified
Published
Oct 4, 2023, 9:15 PM
Modified
Jun 17, 2026, 6:26 AM