OPKSSH up to 0.4.0 JWS authentication bypass

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.4$0-$5k0.00

Summaryinfo

A vulnerability categorized as very critical has been discovered in OPKSSH up to 0.4.0. Affected is an unknown function of the component JWS Handler. The manipulation results in authentication bypass. This vulnerability is identified as CVE-2025-4658. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as very critical has been found in OPKSSH up to 0.4.0. Affected is an unknown functionality of the component JWS Handler. The manipulation with an unknown input leads to a authentication bypass vulnerability. CWE is classifying the issue as CWE-305. The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Versions of OpenPubkey library prior to 0.10.0 contained a vulnerability that would allow a specially crafted JWS to bypass signature verification. As OPKSSH depends on the OpenPubkey library for authentication, this vulnerability in OpenPubkey also applies to OPKSSH versions prior to 0.5.0 and would allow an attacker to bypass OPKSSH authentication.

The weakness was released by Ethan Heilman. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2025-4658 since 05/13/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 10/19/2025).

The vulnerability scanner Nessus provides a plugin with the ID 270269 (Linux Distros Unpatched Vulnerability : CVE-2025-4658), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.5.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (270269). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔍
CNA CVSS-BT Score: 🔍
CNA Vector: 🔍

CVSSv3info

VulDB Meta Base Score: 9.8
VulDB Meta Temp Score: 9.4

VulDB Base Score: 9.8
VulDB Temp Score: 9.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Authentication bypass
CWE: CWE-305 / CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 270269
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-4658

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: OPKSSH 0.5.0

Timelineinfo

05/13/2025 🔍
05/13/2025 +0 days 🔍
05/13/2025 +0 days 🔍
10/19/2025 +159 days 🔍

Sourcesinfo

Advisory: github.com
Researcher: Ethan Heilman
Status: Confirmed

CVE: CVE-2025-4658 (🔍)
GCVE (CVE): GCVE-0-2025-4658
GCVE (VulDB): GCVE-100-308736

Entryinfo

Created: 05/13/2025 19:56
Updated: 10/19/2025 05:33
Changes: 05/13/2025 19:56 (66), 10/19/2025 05:33 (2)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Might our Artificial Intelligence support you?

Check our Alexa App!