CVE-2026-2050: 
NixOS vulnerability analysis and mitigation

CVE-2026-2050 is a heap-based buffer overflow vulnerability in GIMP's HDR file parsing component that allows remote attackers to execute arbitrary code on affected systems. The flaw was reported to the vendor on December 4, 2025, and publicly disclosed on April 15, 2026, via the Zero Day Initiative advisory ZDI-26-282 (ZDI-CAN-28266). Confirmed affected versions include GIMP 3.0.6; Red Hat Enterprise Linux 6, 7, 8, and 9 are also listed as affected due to their bundled GIMP packages. The vulnerability carries a CVSS v3.1 base score of 7.8 (High) (ZDI Advisory, Red Hat Bugzilla, GitHub Advisory).

The vulnerability is rooted in insufficient validation of user-supplied data length before copying it into a heap-allocated buffer during HDR (High Dynamic Range) file parsing, classified as CWE-122 (Heap-based Buffer Overflow) and CWE-131 (Incorrect Calculation of Buffer Size). An attacker crafts a malicious HDR file with oversized data fields that, when parsed by GIMP's HDR loader (implemented via the GEGL library), triggers a heap buffer overflow. Exploitation requires user interaction — the target must open the malicious file, either directly or by visiting a web page that initiates the file open. The fix is tracked in the GEGL project via merge request 241 (ZDI Advisory, GitHub Advisory, Red Hat CSAF).

Successful exploitation allows an attacker to execute arbitrary code in the context of the GIMP process (running as the current user), resulting in high confidentiality, integrity, and availability impact. An attacker could read sensitive files accessible to the user, modify or delete data, or crash the application. While the attack vector is local (the file must be opened on the victim's machine), the delivery mechanism can be remote — e.g., via a malicious email attachment or a web page triggering a file download and open. Lateral movement potential is limited to the privileges of the GIMP process, but code execution could serve as a foothold for further compromise (ZDI Advisory, Red Hat CSAF).

A proof-of-concept exploit reference is publicly available through the Zero Day Initiative advisory published on April 15, 2026, credited to researcher Michael Randrianantenaina. There is no evidence of active in-the-wild exploitation at this time, and the NVD SSVC assessment confirms exploitation status as "none." The EPSS score is approximately 0.55%, placing it in the 42nd percentile for exploitation likelihood within 30 days. The vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog (ZDI Advisory, GitHub Advisory).

1. Craft a malicious HDR file: Create a specially crafted HDR (Radiance RGBE) file with a manipulated header or scanline data that specifies a length value causing an incorrect buffer size calculation in GEGL's HDR parser, resulting in a heap buffer overflow when data is copied.
2. Deliver the payload: Host the malicious HDR file on an attacker-controlled web server or distribute it via email/messaging as an attachment, targeting users known to use GIMP for image editing.
3. Social engineering: Lure the target into opening the file — e.g., by disguising it as a legitimate HDR photograph, a design asset, or embedding a download link in a phishing email or malicious webpage.
4. Trigger the overflow: When the victim opens the file in GIMP, the HDR parsing code (in the GEGL library) copies user-supplied data into an undersized heap buffer without proper length validation, corrupting adjacent heap memory.
5. Achieve code execution: By controlling the overflow data, the attacker can overwrite heap metadata or function pointers to redirect execution flow, ultimately running arbitrary shellcode or commands in the context of the GIMP process and the victim's user account (ZDI Advisory, GitHub Advisory).

• File System: Unexpected .hdr files in download directories, temporary folders, or email attachment staging areas; newly created or modified files in the user's home directory shortly after GIMP was used to open an HDR file.
• Process: Unusual child processes spawned by the GIMP process (e.g., bash, sh, curl, wget, python) immediately after opening an HDR file; GIMP process crashing with a segmentation fault or heap corruption error.
• Network: Outbound network connections from the GIMP process or its child processes to unknown external IP addresses or domains following HDR file parsing; DNS queries for attacker-controlled domains originating from the user's workstation.
• Logs: Application crash logs or core dumps referencing GEGL's HDR loader; system logs showing unexpected process execution under the user account running GIMP shortly after file open events (ZDI Advisory).

GIMP has issued an update addressing this vulnerability; the fix is implemented in the GEGL library via merge request 241, and users should update GIMP and GEGL to the latest patched versions available from their distribution or the official GIMP project. Debian has issued security advisories (DSA-6142-1 and DLA-4487-1) for GEGL, and Mageia has released MGASA-2026-0047; Amazon Linux 2 users should apply ALAS2-2026-3183. Red Hat notes that no practical workaround is available for RHEL 8 and 9 (fix not yet available), and RHEL 6/7 are out of support scope. As an interim measure, users should avoid opening HDR files from untrusted sources and consider disabling HDR file association with GIMP where operationally feasible (ZDI Advisory, Red Hat CSAF, GitHub Advisory).

Red Hat has classified this vulnerability as "Important" severity and opened tracking bug RHBZ#2492593, noting that while user interaction is required (reducing immediate threat), the potential for system compromise warrants a high-priority response. The vulnerability was discovered and responsibly disclosed by researcher Michael Randrianantenaina through the Zero Day Initiative coordinated disclosure program, with a 4+ month disclosure window (December 2025 to April 2026). Multiple Linux distributions including Debian, Mageia, and Amazon Linux have issued security advisories and updates for the underlying GEGL library (ZDI Advisory, Red Hat Bugzilla).