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TI-2025-26993 Aliases CVE-2025-40323GHSA-vv6w-x7vv-rv35

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

Priority LOW 35Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 14 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0014 3rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.15.203, 6.1.159, 6.6.117 +3Red Hat: 4 advisoriesRed Hat: 14 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.12 and later5.15.203, 6.1.159, 6.6.117, 6.12.58, 6.17.8, 6.18Patch availableCNA
  • Linux VendorLinux Affected 2.6.12 and later Fixed in 5.15.203, 6.1.159, 6.6.117, 6.12.58, 6.17.8, 6.18 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.15.203, 6.1.159, 6.6.117, 6.12.58, 6.17.8, 6.18

Red Hat 4 advisories

  • RHSA-2026:72468 Released 2026-09-28 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.169.1.el8_10, kernel-4.18.0-553.169.1.el8_10, kernel-abi-stablelists-4.18.0-553.169.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.169.1.el8_10
  • RHSA-2026:72467 Released 2026-09-28 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-core-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-4.18.0-553.169.1.rt7.510.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-core-4.18.0-553.169.1.rt7.510.el8_10, kernel-rt-debug-4.18.0-553.169.1.rt7.510.el8_10 +7
  • RHSA-2026:71700 Released 2026-09-25 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.52.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.52.1.el9_8, kernel-64k-devel-5.14.0-687.52.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.52.1.el9_8, kernel-64k-5.14.0-687.52.1.el9_8, kernel-64k-core-5.14.0-687.52.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.52.1.el9_8, libperf-5.14.0-687.52.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.52.1.el9_8, kernel-rt-64k-5.14.0-687.52.1.el9_8, kernel-rt-64k-core-5.14.0-687.52.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.52.1.el9_8, kernel-rt-core-5.14.0-687.52.1.el9_8, kernel-rt-debug-5.14.0-687.52.1.el9_8 +9
Show 1 more Red Hat advisories
  • RHSA-2026:71602 Released 2026-09-24 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.60.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.60.1.el10_2, kernel-64k-devel-6.12.0-211.60.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.60.1.el10_2, kernel-64k-6.12.0-211.60.1.el10_2, kernel-64k-core-6.12.0-211.60.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.60.1.el10_2, libperf-6.12.0-211.60.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.60.1.el10_2, kernel-rt-64k-6.12.0-211.60.1.el10_2, kernel-rt-64k-core-6.12.0-211.60.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.60.1.el10_2, kernel-rt-core-6.12.0-211.60.1.el10_2, kernel-rt-debug-6.12.0-211.60.1.el10_2 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:71602
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:71700
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:71602
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:72468
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:71700
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:72468
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:71602
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:71700
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2026:72467
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2026:72467
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:71602
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:71700
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:71602
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:71700
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-40323
  2. 2026-10-03 Alias added: GHSA-vv6w-x7vv-rv35
  3. 2026-10-16 CISA SSVC decision points changed

References

Other 6

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2021-02452 Incorrect authorization in Ubuntu linux kernel KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
See all 21741 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences