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TI-2023-23497 Aliases CVE-2023-43809GHSA-mc97-99j4-vm2v

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

Priority HIGH 72CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-287.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.01217 68th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed soft-serve (charmbracelet): 0.6.2github.com/charmbracelet/soft-serve (Go): 0.6.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
charmbraceletsoft-servebefore 0.6.20.6.2Patch availableCNA
—github.com/charmbracelet/soft-serve (Go)before 0.6.20.6.2Patch availableGHSA-mc97-99j4-vm2v
  • soft-serve Vendorcharmbracelet Affected before 0.6.2 Fixed in 0.6.2 Patch available CNA
  • github.com/charmbracelet/soft-serve (Go) Vendor— Affected before 0.6.2 Fixed in 0.6.2 Patch available GHSA-mc97-99j4-vm2v

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:charm:soft_serve:*:*:*:*:*:go:*:*before 0.6.2Vulnerablecharmbracelet
  • cpe:2.3:a:charm:soft_serve:*:*:*:*:*:go:*:* Versions before 0.6.2 Vulnerable ·charmbracelet

Remediation

  • Fix · CNA soft-serve (charmbracelet) Fixed in 0.6.2
  • Fix · GHSA-mc97-99j4-vm2v github.com/charmbracelet/soft-serve (Go) Fixed in 0.6.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-43809
  2. 2026-10-03 Alias added: GHSA-mc97-99j4-vm2v

References

Exploit 1

Patch 1

Advisory 2

Other 2

  • TI-2026-23661 Soft Serve: SSRF via unvalidated LFS endpoint in repo import CVSS 3.1CRITICAL 9.1
  • TI-2025-39912 Soft Serve is vulnerable to SSRF through its Webhooks CVSS 3.1CRITICAL 9.1
  • TI-2026-25759 Soft Serve: Authenticated repo import can clone server-local private repositories CVSS 4.0HIGH 7.1
  • TI-2026-17863 Soft Serve is missing an authorization check in LFS lock deletion CVSS 3.1MEDIUM 5.4
  • TI-2026-19385 Soft Serve has Critical Authentication Bypass CVSS 4.0HIGH 8.1
  • TI-2025-16079 Soft Serve allows path traversal attacks CVSS 4.0MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences