{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40323","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T07:20:57.186Z","datePublished":"2025-12-08T00:46:50.833Z","dateUpdated":"2026-05-11T21:47:08.588Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T21:47:08.588Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbcon: Set fb_display[i]->mode to NULL when the mode is released\n\nRecently, we discovered the following issue through syzkaller:\n\nBUG: KASAN: slab-use-after-free in fb_mode_is_equal+0x285/0x2f0\nRead of size 4 at addr ff11000001b3c69c by task syz.xxx\n...\nCall Trace:\n <TASK>\n dump_stack_lvl+0xab/0xe0\n print_address_description.constprop.0+0x2c/0x390\n print_report+0xb9/0x280\n kasan_report+0xb8/0xf0\n fb_mode_is_equal+0x285/0x2f0\n fbcon_mode_deleted+0x129/0x180\n fb_set_var+0xe7f/0x11d0\n do_fb_ioctl+0x6a0/0x750\n fb_ioctl+0xe0/0x140\n __x64_sys_ioctl+0x193/0x210\n do_syscall_64+0x5f/0x9c0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nBased on experimentation and analysis, during framebuffer unregistration,\nonly the memory of fb_info->modelist is freed, without setting the\ncorresponding fb_display[i]->mode to NULL for the freed modes. This leads\nto UAF issues during subsequent accesses. Here's an example of reproduction\nsteps:\n1. With /dev/fb0 already registered in the system, load a kernel module\n   to register a new device /dev/fb1;\n2. Set fb1's mode to the global fb_display[] array (via FBIOPUT_CON2FBMAP);\n3. Switch console from fb to VGA (to allow normal rmmod of the ko);\n4. Unload the kernel module, at this point fb1's modelist is freed, leaving\n   a wild pointer in fb_display[];\n5. Trigger the bug via system calls through fb0 attempting to delete a mode\n   from fb0.\n\nAdd a check in do_unregister_framebuffer(): if the mode to be freed exists\nin fb_display[], set the corresponding mode pointer to NULL."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/core/fbcon.c","drivers/video/fbdev/core/fbmem.c","include/linux/fbcon.h"],"versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"39c2c1a2773aaf73e56906e5ef670114eb2d354f","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"4ac18f0e6a6d599ca751c4cd98e522afc8e3d4eb","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"468f78276a37f4c6499385a4ce28f4f57be6655d","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"c079d42f70109512eee49123a843be91d8fa133f","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"de89d19f4f30d9a8de87b9d08c1bd35cb70576d8","status":"affected","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","lessThan":"a1f3058930745d2b938b6b4f5bd9630dc74b26b7","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/core/fbcon.c","drivers/video/fbdev/core/fbmem.c","include/linux/fbcon.h"],"versions":[{"version":"2.6.12","status":"affected"},{"version":"0","lessThan":"2.6.12","status":"unaffected","versionType":"semver"},{"version":"5.15.203","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.159","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.117","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.58","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.17.8","lessThanOrEqual":"6.17.*","status":"unaffected","versionType":"semver"},{"version":"6.18","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.159"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.117"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.58"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.17.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/39c2c1a2773aaf73e56906e5ef670114eb2d354f"},{"url":"https://git.kernel.org/stable/c/4ac18f0e6a6d599ca751c4cd98e522afc8e3d4eb"},{"url":"https://git.kernel.org/stable/c/468f78276a37f4c6499385a4ce28f4f57be6655d"},{"url":"https://git.kernel.org/stable/c/c079d42f70109512eee49123a843be91d8fa133f"},{"url":"https://git.kernel.org/stable/c/de89d19f4f30d9a8de87b9d08c1bd35cb70576d8"},{"url":"https://git.kernel.org/stable/c/a1f3058930745d2b938b6b4f5bd9630dc74b26b7"}],"title":"fbcon: Set fb_display[i]->mode to NULL when the mode is released","x_generator":{"engine":"bippy-1.2.0"}}}}