CVE-2025-8114: libssh Vulnerability Leads to Potential Crash via NULL Pointer Dereference
Hey everyone, it's your friendly neighborhood security blogger back with another important update. Today, we're diving into CVE-2025-8114, a vulnerability affecting libssh, a widely used library for implementing the SSH protocol. This flaw can potentially lead to a crash due to a NULL pointer dereference, impacting both client and server applications using the library.
Vulnerability Details
- CVE ID: CVE-2025-8114
- Description: A flaw was found in libssh. During the key exchange (KEX) process, an allocation failure in cryptographic functions may lead to a NULL pointer dereference when calculating the session ID. This issue can cause the client or server to crash.
- CVSS Score: 4.7 (MEDIUM)
- CVSS Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- CVSS Explanation:
- AV:L (Attack Vector: Local): An attacker needs local access to the system.
- AC:H (Attack Complexity: High): Exploitation requires specific conditions to exist, increasing the difficulty.
- PR:L (Privileges Required: Low): An attacker needs low-level privileges to exploit the vulnerability.
- UI:N (User Interaction: None): No user interaction is required.
- S:U (Scope: Unchanged): The vulnerability's impact is limited to the affected component.
- C:N (Confidentiality Impact: None): There is no impact on confidentiality.
- I:N (Integrity Impact: None): There is no impact on integrity.
- A:H (Availability Impact: High): The vulnerability can lead to a denial-of-service condition by causing a crash.
- Exploit Requirements: The attacker needs local access and low privileges on the system where libssh is used. Specific conditions during key exchange must trigger the allocation failure.
- Affected Vendor: libssh
- Affected Product: libssh library
- Affected Version: Affected versions are prior to patched releases (To be determined).
- CWE: CWE-476 - NULL Pointer Dereference. This occurs when the program attempts to use a pointer that has a value of NULL, leading to a crash or unexpected behavior.
Timeline of Events
- 2025-07-24: CVE assigned and vulnerability reported.
- TBD: Patch release for libssh.
Exploitability & Real-World Risk
While the attack complexity is rated as high, meaning specific conditions need to be met for exploitation, the potential for a denial-of-service (DoS) attack is real. An attacker who can trigger the allocation failure during the key exchange process can cause the affected application to crash. In a server environment, this could disrupt services and impact availability.
Recommendations
- Apply Patches: Once available, promptly apply the security patches released by the libssh project to address this vulnerability.
- Monitor Systems: Monitor systems utilizing libssh for unexpected crashes or errors during SSH connections.
- Best Practices: Follow secure coding practices to prevent NULL pointer dereferences in applications using libssh.
Technical Insight
The vulnerability stems from a potential allocation failure during the session ID calculation within the key exchange process. If memory allocation fails and the program doesn't properly handle this failure, it can lead to a NULL pointer being used later in the code, resulting in a crash. This highlights the importance of robust error handling in cryptographic libraries.
Credit to Researcher(s)
Credit to the researchers who discovered and reported this vulnerability. Details will be updated as more information becomes available.
References
Tags
#Security #CVE-2025-8114 #libssh #NULLPointerDereference #Crash #KEX #RedHat
Summary: A NULL pointer dereference vulnerability exists in libssh during the key exchange process, potentially causing a crash on both client and server systems. Patching is essential to mitigate this denial-of-service risk.
CVE ID: CVE-2025-8114
Risk Analysis: Successful exploitation of this vulnerability can lead to a denial-of-service condition, disrupting services and impacting availability. The complexity of exploitation is high, requiring specific conditions to trigger the flaw.
Recommendation: Apply the security patches released by the libssh project as soon as they become available. Monitor systems for unexpected crashes or errors during SSH connections and follow secure coding practices to prevent NULL pointer dereferences.
Timeline
- 2025-07-24: CVE assigned and vulnerability reported.
- TBD: Patch release for libssh.