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

CVE-2023-43809 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Impact

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.

Patches

Users should upgrade to the latest Soft Serve version v0.6.2 to receive the patch for this issue.

Workarounds

To workaround this vulnerability without upgrading, users can temporarily disable Keyboard-Interactive SSH Authentication using the allow-keyless setting.

References

https://github.com/charmbracelet/soft-serve/issues/389

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2023-10-02 23:30:39 UTC
Updated
2023-11-08 05:01:48 UTC
GitHub reviewed
2023-10-02 23:30:39 UTC
NVD published
2023-10-04 21:15:10 UTC

EPSS Score

Score Percentile
0.18% 40.42%

CVSS Scores

Base score Version Severity Vector
7.5 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

Type Value
GHSA GHSA-mc97-99j4-vm2v ↗
CVE CVE-2023-43809 ↗

CWEs

CWE id Name
CWE-287 Improper Authentication

Credits

  • JJGadgets (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
go github.com/charmbracelet/soft-serve < 0.6.2 0.6.2 —

References

cvelogic Threat Intelligence