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.
| Métrique | Valeur | Interprétation |
|---|---|---|
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AV (Vecteur d'Attaque)
Attack Vector
|
Adjacent (A)
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Exploit nécessite un accès au segment réseau local |
|
AC (Complexité d'Attaque)
Attack Complexity
|
High (H)
|
Conditions spécifiques doivent être réunies pour exploiter |
|
PR (Privilèges Requis)
Privileges Required
|
Low (L)
|
Authentifié avec compte utilisateur basique |
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UI (Interaction Utilisateur)
User Interaction
|
None (N)
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Aucune interaction utilisateur nécessaire |
|
S (Périmètre)
Scope
|
Unchanged (U)
|
Impact reste dans le périmètre du composant compromis |
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C (Impact Confidentialité)
Confidentiality Impact
|
Low (L)
|
Divulgation limitée d'informations |
|
I (Impact Intégrité)
Integrity Impact
|
Low (L)
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Modification limitée des données possible |
|
A (Impact Disponibilité)
Availability Impact
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None (N)
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Aucune interruption de service |
[BIGSLEEP-434612419] CUPS-Filters has heap-buffer-overflow write in `cfImageLut()`