CVE-2026-77207
Description
A null pointer dereference flaw was found in Libreswan's PKCS#7 certificate payload handling. When processing a crafted IKEv2 IKE_AUTH packet containing a PKCS#7 bundle with a certificate revocation list but no certificates, Libreswan may dereference a null pointer, causing the pluto daemon to crash and restart. A remote, unauthenticated attacker could repeatedly trigger this flaw to cause a denial of service.
Statement
This vulnerability is rated as Moderate impact for Red Hat because exploitation requires Libreswan to be deployed, configured, and running as an IKEv2 endpoint, which is not the default configuration of a general-purpose Red Hat Enterprise Linux installation. A remote, unauthenticated attacker can send a crafted IKEv2 packet to crash the Libreswan daemon, potentially disrupting VPN connectivity. Although, systemd supervision typically restarts the crashed process automatically, reducing the persistence of service interruptions, repeated exploitation can cause continued denial of service.
Mitigation
Red Hat is not aware of a practical temporary workaround that fully mitigates this issue or meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. Customers are advised to apply the relevant security updates when/if they become available.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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