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CVE-2026-53401
fbdev: omap2: fix use-after-free in omapfb_mmap
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/video. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-53401 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| Debian 14forky | fixed | 7.1.3-1 | Update the kernel and reboot. Fixed in 7.1.3-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.3-1 | Update the kernel and reboot. Fixed in 7.1.3-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
omapfb_mmap() has a race condition with OMAPFB_SETUP_PLANE ioctl that can lead to use-after-free: The fb_mmap() entry point holds mm_lock but not lock (fb_info->lock), while ioctl handlers like OMAPFB_SETUP_PLANE hold lock but not mm_lock. This allows concurrent execution. In omapfb_mmap(): 1. rg = omapfb_get_mem_region(ofbi->region); // Get old region ref 2. start = omapfb_get_region_paddr(ofbi); // Read from NEW region 3. len = fix->smem_len; // Read from NEW region 4. vm_iomap_memory(vma, start, len); // Map NEW region memory 5. atomic_inc(&rg->map_count); // Increment OLD region! Concurrently, OMAPFB_SETUP_PLANE can: - Reassign ofbi->region = new_rg - Update fix->smem_len - OMAPFB_SETUP_MEM then checks NEW region's map_count (0!) and frees it This leaves userspace with a mapping to freed physical memory. The fix is to read all required values (start, len) from the same region reference (rg) that will have its map_count incremented, preventing the region from being freed while still mapped.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/video/fbdev/omap2/omapfb/omapfb-main.c
- What this is
- OMAP DISPLAY SUBSYSTEM and FRAMEBUFFER SUPPORT (DSS2)MAINTAINERS section matched on drivers/video/fbdev/omap2/ · linux-omap@vger.kernel.org · Orphan
- Kernel module
- none to look for. The file would have gone into omap2fb, and Debian does not compile it into that module, so finding omap2fb in lsmod would say nothing about this CVE.
Check it on the machine
grep -w CONFIG_FB_OMAP2 /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switch
- CONFIG_FB_OMAP2
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-07-19 (3 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 2.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/video
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.36 | 6.18.57 | 8363c219d88e |
| 2.6.36 | 7.1.3 | 6eb6ebcc8590 |
| 2.6.36 | 7.2 | 7958e67375aa |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- Exploitation requires local syscalls (mmap and OMAPFB ioctls) against /dev/fb*; there is no network, adjacent-wireless, or physical-device insertion path to this driver code.
- AC:LAttack complexity, low
- The attacker fully controls both sides of the race by opening /dev/fb and running concurrent mmap and OMAPFB_SETUP_PLANE/OMAPFB_SETUP_MEM ioctl threads, with no conditions outside attacker influence required for success.
- PR:LPrivileges required, low
- Exploitation requires only the ability to open the framebuffer character device and issue its ioctls, which on OMAP embedded/kiosk deployments is typically granted to a local application user (video group or equivalent), not real root.
- UI:NUser interaction, none
- No victim interaction is required; the attacker triggers the race entirely through their own threads operating on a framebuffer device they can already open.
- S:UScope, unchanged
- Impact is confined to escalating within the same OS security boundary (userspace gaining read/write access to freed kernel/DMA physical memory), not a VM escape or cross-guest boundary crossing.
- C:HConfidentiality impact, high
- The use-after-free leaves userspace mapped to freed physical pages that can be reallocated with sensitive kernel or DMA data, enabling arbitrary memory disclosure.
- I:HIntegrity impact, high
- The stale userspace mapping provides writable access to freed physical memory, enabling corruption of subsequently allocated kernel or DMA buffers and potential control-flow hijacking.
- A:HAvailability impact, high
- Use-after-free of DMA framebuffer memory can cause kernel oopses or panics when freed pages are reused, and the UAF itself constitutes a high availability impact even before full exploitation.