A buffer overflow in the EGifGCBToExtension function of giflib version 5.2.2 allows a remote attacker to overwrite the memory of an existing Graphic Control Extension block when it fails to validate the block's allocated size. The flaw can be triggered by a malicious GIF file, resulting in a denial of service by crashing the application or terminating the associated process. This attack targets memory integrity, reflected in CWE‑787. The impact is a loss of availability for any service relying on giflib to process GIF images.

The vulnerability affects the giflib library, version 5.2.2, distributed by giflib_project. Systems that integrate this specific library and decode GIF files may be susceptible. No other vendors or version ranges were identified in the advisory.

The CVSS score of 8.2 indicates a high severity rating, while the EPSS score of less than 1 percent suggests a low probability of exploitation in the wild. The flaw is not listed in the CISA KEV catalog, which further indicates that no widespread, active exploitation is known. The likely attack surface is remote, through a crafted GIF file that a user or client submits to a process using giflib. These conditions mean that administrators of affected systems should treat the issue carefully, applying a fix and monitoring for attempts to exploit the overflow.