Denial of Service and potential information disclosure via crafted EXR file

Summary

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. In versions 3.4.0 through 3.4.11, the HTJ2K (High-Throughput JPEG 2000) decoder, ht_undo_impl() in OpenEXRCore is vulnerable to a heap-buffer-overflow READ. The ht_undo_imp function copies decoded pixels out of a per-line OpenJPH buffer using the EXR channel's declared width as the iteration count. The codestream embedded in the EXR chunk can declare different (smaller) tile/line dimensions than the EXR header advertises, but ht_undo_impl() does not validate this — it pulls width 32-bit samples from cur_line->i32[] without checking the OpenJPH line buffer's actual length. A crafted EXR file produces a 4-byte heap-buffer-overflow READ immediately after a buffer allocated by ojph::local::codestream::finalize_alloc(). The bug is reachable through the standard scanline-decode entry point used by every consumer of exr_decoding_run/Imf::checkOpenEXRFile, including thumbnailers, asset pipelines, and the exrcheck utility — i.e. any application that opens untrusted EXR files. The result is a deterministic crash (DoS) and potential adjacent-heap leak. This issue has been fixed in version 3.4.12. A flaw was found in the OpenEXR image library. If an application opens a maliciously crafted EXR image file, it triggers a memory error. An attacker can use this to crash the application—causing a denial of service (DoS)—and potentially view sensitive information from the application's memory. Any system that processes untrusted EXR files is at risk. This flaw in the OpenEXR library allows attackers to crash applications or potentially view sensitive memory data by providing a specially crafted image file. Systems that automatically process untrusted EXR files (like asset pipelines or thumbnailers) are at the highest risk. Red Hat severity: Important — CVSS 7.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H). Weakness: CWE-125. No fixing RHSA erratum has published yet; monitor the Red Hat CVE page and patch when it ships. Will not fix / out of support: Red Hat Enterprise Linux 6.