GIMP CVE-2025-10921

Exploitation requires the victim to open an attacker-controlled Radiance HDR (.hdr) image file in GIMP (or a page that causes such a file to be opened), triggering the vulnerable HDR parser in the GEGL library that fails to validate the length of user-supplied data before copying it to a heap buffer. The key limiting factors are: no remote network trigger (AV:L) and mandatory user interaction (UI:R), meaning the attack cannot succeed without social engineering; exploitation runs only with the privileges of the user who opened the file (no privilege escalation implied); and it is constrained to installations processing the HDR format via vulnerable GEGL/GIMP builds (GIMP 3.0.4 and the GEGL version shipped on Debian 11 are the confirmed affected references).

This is a credible but not emergency-priority vulnerability. The CVSS 3.0 base score of 7.8 (HIGH) is driven by the triple-High impact (C:H/I:H/A:H) and low attack complexity, but the local attack vector (AV:L) and required user interaction (UI:R) substantially temper real-world risk: exploitation is not remote-automatable and depends on a victim opening a malicious HDR file or visiting a page that delivers one. Note the common ZDI framing tension - the description calls these 'remote attackers' and references a malicious page, yet the CVSS vector is correctly AV:L because the attacker does not touch the target directly; code runs only when the user locally opens attacker-supplied content. No EPSS score, SSVC decision, KEV listing, or public POC is present in the provided data, so there is no evidence of active exploitation or mass-scanning pressure - consistent with a file-format parser bug that requires social engineering rather than a server-side flaw. The CWE-122 heap overflow with lack of length validation is a classic memory-corruption primitive, and a vendor patch exists (GEGL commit), so the practical priority is to patch GIMP/GEGL on desktop and multi-user systems and treat untrusted HDR files as suspect, rather than to respond as if to a wormable remote threat.

An attacker crafts a malicious Radiance HDR image file with a length field that overflows a heap buffer in GIMP's parsing routine (implemented in the GEGL library) and sends it to a victim via email, a shared drive, or a web page offering a downloadable image. When the victim opens the file in GIMP, the oversized user-supplied data is copied into the heap buffer, corrupting memory and allowing arbitrary code execution in the context of the GIMP process. No public exploit was identified at time of analysis, so this scenario is based on the described flaw rather than a confirmed weaponized sample.