cups-filters contains backends, filters, and other software required to get the cups printing service working on operating systems other than macos. In versions 2.0.1 and prior, a heap-buffer-overflow vulnerability in the rastertopclx filter causes the program to crash with a segmentation fault when processing maliciously crafted input data. This issue can be exploited to trigger memory corruption, potentially leading to arbitrary code execution. This issue has been patched via commit 956283c.

cups-filters contains backends, filters, and other software required to get the cups printing service working on operating systems other than macos. In cups-filters prior to 1.28.18, by crafting a PDF file with a large MediaBox value, an attacker can cause CUPS-Filter 1.x’s pdftoraster tool to write beyond the bounds of an array. First, a PDF with a large MediaBox width value causes header.cupsWidth to become large. Next, the calculation of bytesPerLine = (header.cupsBitsPerPixel header.cupsWidth + 7) / 8 overflows, resulting in a small value. Then, lineBuf is allocated with the small bytesPerLine size. Finally, convertLineChunked calls writePixel8, which attempts to write to lineBuf outside of its buffer size (out of bounds write). In libcupsfilters, the maintainers found the same bytesPerLine multiplication without overflow check, but the provided test case does not cause an overflow there, because the values are different. Commit 50d94ca0f2fa6177613c97c59791bde568631865 contains a patch, which is incorporated into cups-filters version 1.28.18.

CUPS is a standards-based, open-source printing system, and libcupsfilters contains the code of the filters of the former cups-filters package as library functions to be used for the data format conversion tasks needed in Printer Applications. In CUPS-Filters versions up to and including 1.28.17 and libscupsfilters versions 2.0.0 through 2.1.1, CUPS-Filters's imagetoraster filter has an out of bounds read/write vulnerability in the processing of TIFF image files. While the pixel buffer is allocated with the number of pixels times a pre-calculated bytes-per-pixel value, the function which processes these pixels is called with a size of the number of pixels times 3. When suitable inputs are passed, the bytes-per-pixel value can be set to 1 and bytes outside of the buffer bounds get processed. In order to trigger the bug, an attacker must issue a print job with a crafted TIFF file, and pass appropriate print job options to control the bytes-per-pixel value of the output format. They must choose a printer configuration under which the imagetoraster filter or its C-function equivalent cfFilterImageToRaster() gets invoked. The vulnerability exists in both CUPS-Filters 1.x and the successor library libcupsfilters (CUPS-Filters 2.x). In CUPS-Filters 2.x, the vulnerable function is cfImageReadTIFF() in libcupsfilters. When this function is invoked as part of cfFilterImageToRaster(), the caller passes a look-up-table during whose processing the out of bounds memory access happens. In CUPS-Filters 1.x, the equivalent functions are all found in the cups-filters repository, which is not split into subprojects yet, and the vulnerable code is in cupsImageReadTIFF(), which is called through cupsImageOpen() from the imagetoraster tool. A patch is available in commit b69dfacec7f176281782e2f7ac44f04bf9633cfa.

Simone Margaritelli discovered that libcupsfilters incorrectly sanitized IPP data when creating PPD files. A remote attacker could possibly use this issue to manipulate PPD files and execute arbitrary code when a printer is used.