Tga - CraftedSignal Threat Feedhttps://feed.craftedsignal.io/tags/tga/Trending threats, MITRE ATT&CK coverage, and detection metadata. Fed continuously.Hugoenhello@craftedsignal.iohello@craftedsignal.ioWed, 03 Jan 2024 12:00:00 +0000SAIL Library TGA RLE Decoder Heap Overflow Vulnerabilityhttps://feed.craftedsignal.io/briefs/2024-01-sail-tga-rle-heap-overflow/Wed, 03 Jan 2024 12:00:00 +0000hello@craftedsignal.iohttps://feed.craftedsignal.io/briefs/2024-01-sail-tga-rle-heap-overflow/The SAIL library versions before commit 45d48d1f2e8e0d73e80bc1fd5310cb57f4547302 are vulnerable to a heap overflow in the TGA codec's RLE decoder, where the raw-packet path lacks bounds checking, potentially leading to privilege escalation via crafted image files.The SAIL library, a cross-platform solution for image loading and saving, is susceptible to a critical vulnerability (CVE-2026-40494) affecting versions prior to commit 45d48d1f2e8e0d73e80bc1fd5310cb57f4547302. The vulnerability resides within the Truevision Graphics Adapter (TGA) codec's Run-Length Encoding (RLE) decoder specifically in tga.c. The flaw stems from an asymmetric bounds check in the RLE decoder. While the run-packet path includes necessary bounds checking, the raw-packet path lacks this safeguard. This omission allows a malicious actor to craft a TGA image that, when processed by a vulnerable application, triggers a heap overflow by writing up to 496 bytes beyond the allocated buffer. This vulnerability poses a significant risk as it can be exploited to achieve arbitrary code execution and privilege escalation on systems utilizing the affected SAIL library. The scope of targeting includes any application utilizing the vulnerable SAIL library on Windows, Linux, or macOS.

Attack Chain

  1. An attacker crafts a malicious TGA image file exploiting the missing bounds check in the RLE decoder's raw-packet path.
  2. The attacker delivers the malicious TGA image to a target system, potentially via a website upload, email attachment, or other file transfer mechanisms.
  3. A vulnerable application using the SAIL library attempts to load the malicious TGA image.
  4. The TGA codec's RLE decoder processes the image data within tga.c.
  5. Due to the absence of bounds checking in the raw-packet path (lines 305-311), the decoder writes attacker-controlled data beyond the allocated heap buffer.
  6. The heap overflow corrupts adjacent memory regions, potentially overwriting critical data structures or function pointers.
  7. The corrupted memory leads to a crash or, more critically, allows the attacker to hijack program execution.
  8. Successful exploitation enables the attacker to execute arbitrary code with the privileges of the vulnerable application, leading to privilege escalation.

Impact

Successful exploitation of CVE-2026-40494 allows an attacker to achieve arbitrary code execution with the privileges of the application using the vulnerable SAIL library. The impact is severe, as it can lead to complete system compromise, data exfiltration, or denial of service. The number of potential victims is broad, including any user or organization employing applications that rely on the affected SAIL library for image processing across various sectors. While specific victim numbers remain unknown, the cross-platform nature of the library suggests widespread potential impact.

Recommendation

  • Upgrade the SAIL library to a version containing the fix for CVE-2026-40494, specifically commit 45d48d1f2e8e0d73e80bc1fd5310cb57f4547302.
  • Deploy the Sigma rules provided in this brief to your SIEM to detect potential exploitation attempts.
  • Implement input validation and sanitization measures to restrict the types and sizes of image files processed by applications using the SAIL library.
  • Monitor applications using the SAIL library for unexpected crashes or abnormal behavior, which could indicate exploitation attempts.
  • Enable process creation logging with command line arguments to allow detection of suspicious processes spawned by applications processing images.
]]>criticaladvisoryCVE-2026-40494sailtgaheap-overflowprivilege-escalation