Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2025-40323— fbcon: Set fb_display[i]->mode to NULL when the mode is released

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未设置fb_display[i]->mode为NULL，可能导致释放后重用。

CVSS 7.8 · High EPSS 0.14% · P3

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 39c2c1a2773aaf73e56906e5ef670114eb2d354f affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 4ac18f0e6a6d599ca751c4cd98e522afc8e3d4eb affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 468f78276a37f4c6499385a4ce28f4f57be6655d affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< c079d42f70109512eee49123a843be91d8fa133f affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< de89d19f4f30d9a8de87b9d08c1bd35cb70576d8 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< a1f3058930745d2b938b6b4f5bd9630dc74b26b7 affected
2.6.12 affected
< 2.6.12 unaffected
… +6 more rows
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2025-40323

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
fbcon: Set fb_display[i]->mode to NULL when the mode is released
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: fbcon: Set fb_display[i]->mode to NULL when the mode is released Recently, we discovered the following issue through syzkaller: BUG: KASAN: slab-use-after-free in fb_mode_is_equal+0x285/0x2f0 Read of size 4 at addr ff11000001b3c69c by task syz.xxx ... Call Trace: <TASK> dump_stack_lvl+0xab/0xe0 print_address_description.constprop.0+0x2c/0x390 print_report+0xb9/0x280 kasan_report+0xb8/0xf0 fb_mode_is_equal+0x285/0x2f0 fbcon_mode_deleted+0x129/0x180 fb_set_var+0xe7f/0x11d0 do_fb_ioctl+0x6a0/0x750 fb_ioctl+0xe0/0x140 __x64_sys_ioctl+0x193/0x210 do_syscall_64+0x5f/0x9c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e Based on experimentation and analysis, during framebuffer unregistration, only the memory of fb_info->modelist is freed, without setting the corresponding fb_display[i]->mode to NULL for the freed modes. This leads to UAF issues during subsequent accesses. Here's an example of reproduction steps: 1. With /dev/fb0 already registered in the system, load a kernel module to register a new device /dev/fb1; 2. Set fb1's mode to the global fb_display[] array (via FBIOPUT_CON2FBMAP); 3. Switch console from fb to VGA (to allow normal rmmod of the ko); 4. Unload the kernel module, at this point fb1's modelist is freed, leaving a wild pointer in fb_display[]; 5. Trigger the bug via system calls through fb0 attempting to delete a mode from fb0. Add a check in do_unregister_framebuffer(): if the mode to be freed exists in fb_display[], set the corresponding mode pointer to NULL.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于未设置fb_display[i]->mode为NULL，可能导致释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ~ 39c2c1a2773aaf73e56906e5ef670114eb2d354f -
Linux Linux 2.6.12 -

II. Public POCs for CVE-2025-40323

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2025-40323

请登录查看更多情报信息。

Same Patch Batch · Linux · 2025-12-08 · 82 CVEs total

CVE-2023-53751 9.8 CRITICAL cifs: fix potential use-after-free bugs in TCP_Server_Info::hostname
CVE-2025-40320 9.8 CRITICAL smb: client: fix potential cfid UAF in smb2_query_info_compound
CVE-2023-53769 9.3 CRITICAL virt/coco/sev-guest: Double-buffer messages
CVE-2025-40318 8.8 HIGH Bluetooth: hci_sync: fix race in hci_cmd_sync_dequeue_once
CVE-2023-53764 8.8 HIGH wifi: ath12k: Handle lock during peer_id find
CVE-2023-53762 8.8 HIGH Bluetooth: hci_sync: Fix UAF in hci_disconnect_all_sync
CVE-2025-40292 8.4 HIGH virtio-net: fix received length check in big packets
CVE-2025-40309 8.0 HIGH Bluetooth: SCO: Fix UAF on sco_conn_free
CVE-2025-40302 7.8 HIGH media: videobuf2: forbid remove_bufs when legacy fileio is active
CVE-2023-53763 7.8 HIGH Revert "f2fs: fix to do sanity check on extent cache correctly"
CVE-2023-53768 7.8 HIGH regmap-irq: Fix out-of-bounds access when allocating config buffers
CVE-2025-40297 7.8 HIGH net: bridge: fix use-after-free due to MST port state bypass
CVE-2022-50630 7.8 HIGH mm: hugetlb: fix UAF in hugetlb_handle_userfault
CVE-2022-50623 7.8 HIGH fpga: prevent integer overflow in dfl_feature_ioctl_set_irq()
CVE-2023-53759 7.8 HIGH HID: hidraw: fix data race on device refcount
CVE-2025-40317 7.8 HIGH regmap: slimbus: fix bus_context pointer in regmap init calls
CVE-2025-40319 7.8 HIGH bpf: Sync pending IRQ work before freeing ring buffer
CVE-2023-53747 7.8 HIGH vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF
CVE-2023-53753 7.8 HIGH drm/amd/display: fix mapping to non-allocated address
CVE-2023-53752 7.8 HIGH net: deal with integer overflows in kmalloc_reserve()

Showing top 20 of 82 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2025-40323

No comments yet

Leave a comment