Description

A flaw was found in GNOME Shell. When processing icons from a remote search provider via D-Bus, the system fails to validate the icon's declared dimensions against the actual data buffer size. A malicious or compromised remote search provider could exploit this by providing oversized icon dimensions, leading to an out-of-bounds read. This can cause the GNOME Shell process to crash, disrupting the user's session, and potentially disclose sensitive information from adjacent memory.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.1",
  "pubDate": "2026-09-15T11:17:12.580Z",
  "pubdate": "2026-09-15T11:17:12.580Z",
  "executiveSummary": "A critical vulnerability exists within GNOME Shell regarding the processing of icons provided by remote search providers via D-Bus. The flaw stems from insufficient input validation concerning icon dimensions provided in the D-Bus communication protocol. By failing to verify the consistency between the declared icon dimensions and the actual size of the transmitted data buffer, the system becomes susceptible to an out-of-bounds memory read. This vulnerability affects the GNOME Shell process, which is central to the user environment, posing a risk to both system availability and data confidentiality. An attacker acting through a malicious or compromised remote search provider can trigger a memory access violation. Successful exploitation results in a denial-of-service condition due to a process crash, effectively terminating the user session. Furthermore, the out-of-bounds access may allow for the unintended disclosure of sensitive information residing in adjacent memory segments, potentially leaking credentials, tokens, or other private process data. This vulnerability requires the user to interact with a compromised or malicious search provider, making the impact dependent on the integration of third-party search extensions or remote providers within the GNOME environment.",
  "technicalDetails": "The vulnerability is located in the GNOME Shell component responsible for parsing icon metadata received over the D-Bus interface from remote search providers. The root cause is a failure in the validation logic to enforce bounds checking on image data structure parameters. When a search provider sends an icon payload, it specifies dimensions (height and width) along with a data buffer.\nThe application logic trusts the declared dimensions provided in the D-Bus message without verifying that they correspond to the actual byte size of the provided memory buffer. If an attacker specifies dimensions that exceed the buffer size allocated for the icon data, the application subsequently attempts to perform memory operations—typically rendering or processing the icon—based on these malicious dimensions. Because the buffer is smaller than the area the application expects to read, the process performs an out-of-bounds memory read.\nThe attack flow begins when a malicious or compromised search provider registers with the GNOME Shell via D-Bus. Upon a search query, the provider returns a response containing a crafted icon descriptor. When GNOME Shell processes this response, it interprets the oversized dimensions and attempts to access memory at offsets that reside outside the intended buffer. This operation results in a segmentation fault or a memory exception, triggering a GNOME Shell crash. Because GNOME Shell is a critical component of the graphical desktop environment, this crash results in the termination of the user's session, leading to a loss of unsaved work and potential temporary denial of service.\nBeyond the crash, the memory access violation facilitates information disclosure. Because the application processes memory following the actual buffer, the contents of neighboring memory segments are read. If the application exposes these values—for instance, by rendering them in the UI or transmitting them—an attacker could exfiltrate sensitive data from the process heap. This vulnerability does not strictly require high-privileged access, provided the attacker can influence the search results presented to the user. Exposure is inherent in the D-Bus architecture, which allows components to communicate; however, the vulnerability is exposed only when the system parses malicious input from an external provider. There are no authentication requirements for the D-Bus interface in this context, as the vulnerability is triggered during standard interaction with search providers."
}