CVE-2025-71295: Medium Vulnerability in Linux Kernel

CVE-2025-71295 is a medium-severity vulnerability affecting the Linux kernel. This vulnerability allows attackers to cause a null pointer dereference when the function try_to_free_buffers() is called on folios that lack associated buffers. This can occur when filemap_release_folio() is invoked on a folio belonging to a mapping configured with the AS_RELEASE_ALWAYS flag but without a defined release_folio operation. As a result, the system may encounter unexpected behavior, potentially leading to application crashes or system instability.

The vulnerability has a CVSS score of 5.5, indicating medium severity. This level of vulnerability is significant as it poses a risk to the availability of systems running affected versions of the Linux kernel. The vulnerability was published on May 6, 2026, and it has been analyzed for potential exploitation.

Risk to organizations includes potential downtime and service disruptions, particularly if the vulnerability is exploited in environments where the Linux kernel is critical for operations. Organizations should prioritize patching affected versions to mitigate risks associated with this vulnerability.

Currently, there are no known exploits or proof-of-concept code available for CVE-2025-71295. However, the nature of the vulnerability means that organizations should remain vigilant and proactive in their security practices.

Organizations should prioritize patching immediately.

Vulnerability Details

In the Linux kernel, the following vulnerability has been resolved: fs/buffer: add alert in try_to_free_buffers() for folios without buffers try_to_free_buffers() can be called on folios with no buffers attached when filemap_release_folio() is invoked on a folio belonging to a mapping with AS_RELEASE_ALWAYS set but no release_folio operation defined. In such cases, folio_needs_release() returns true because of the AS_RELEASE_ALWAYS flag, but the folio has no private buffer data. This causes try_to_free_buffers() to call drop_buffers() on a folio with no buffers, leading to a null pointer dereference. Adding a check in try_to_free_buffers() to return early if the folio has no buffers attached, with WARN_ON_ONCE() to alert about the misconfiguration. This provides defensive hardening.

Technical Analysis

The root cause of CVE-2025-71295 lies in the Linux kernel's handling of folios and buffers. When filemap_release_folio() is called on a folio with the AS_RELEASE_ALWAYS flag set, the kernel expects that the folio will have associated private buffer data. However, if the folio does not contain any buffers, a null pointer dereference occurs when try_to_free_buffers() is invoked.

This vulnerability can be exploited locally, requiring low privileges to trigger the issue. The attack complexity is classified as low, meaning that an attacker with access to the system could potentially exploit this vulnerability without requiring any user interaction. The impact on availability is high, as the null pointer dereference can lead to crashes or instability in the kernel.

Risk & Impact Analysis

The real-world deployment risk of CVE-2025-71295 is significant. Organizations running the affected versions of the Linux kernel could face system crashes or instability, particularly in environments where high availability is critical. The potential blast radius increases in systems that utilize the Linux kernel for essential services. Given the medium severity and high availability impact, organizations should assess their exposure and prioritize remediation efforts.

Organizations should address in priority patch cycle.

Exploitation Status

Affected Versions

The following versions of the Linux kernel are affected by CVE-2025-71295: - Versions 6.1.72 to 6.1.165 (exclusive) - Versions 6.2 to 6.6.128 (exclusive) - Versions 6.7 to 6.12.75 (exclusive) - Versions 6.13 to 6.18.16 (exclusive) - Versions 6.19 to 6.19.6 (exclusive)

Mitigation & Remediation

To mitigate the risk associated with CVE-2025-71295, organizations should apply the necessary patches as soon as they are available. The patches for this vulnerability can be found in the official Linux kernel repositories. It's crucial to stay updated with the latest kernel releases to ensure that all security patches are applied. If a patch is not available or cannot be applied immediately, consider implementing temporary workarounds such as restricting access to systems running vulnerable kernel versions.

Organizations may also benefit from conducting a thorough security assessment, which can include application security assessments to identify and remediate potential weaknesses.

Detection Guidance

Organizations should monitor logs for indicators of potential exploitation attempts, which may include abnormal system behavior or unexpected crashes related to buffer management. Additionally, keep an eye out for behavioral anomalies that could suggest exploitation of this vulnerability.

AppSecure Threat Intelligence Insight

The long-term significance of CVE-2025-71295 underscores the necessity for proactive security management in the Linux environment. As organizations increasingly rely on Linux for critical infrastructure, vulnerabilities such as this one highlight the importance of maintaining up-to-date systems and implementing robust security practices.

Security teams should take note of the patterns this vulnerability represents, especially in areas related to buffer management and kernel stability. To bolster defenses against similar issues, organizations can consider engaging in penetration testing to uncover potential weaknesses in their systems.

Overall, organizations should prioritize their security posture to reduce the likelihood of exploitation and enhance their resilience against future vulnerabilities.

For further insights, organizations may refer to our blog on penetration testing methodology and how it can help in identifying and mitigating vulnerabilities effectively.