fbdev: omap2: fix use-after-free in omapfb_mmap
CVE-2026-53401 · published 19 Jul 2026
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-53401?
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Who is affected
- Linux Linux: 078ff546a806b2c2ab74c25c8edd4c6d4680656a to < 5e10b1747547c3815e90d28166e92144835e065f, 078ff546a806b2c2ab74c25c8edd4c6d4680656a to < 986d5fafb73b8b866651399934b66d690f49135a, 078ff546a806b2c2ab74c25c8edd4c6d4680656a to < 8363c219d88e78daaee5665117a0380442989338, 078ff546a806b2c2ab74c25c8edd4c6d4680656a to < 6eb6ebcc8590007ad59ddccc8b5f9201655b33f8
- Linux Linux: 2.6.36
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
fbdev: omap2: fix use-after-free in omapfb_mmap
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.
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/5e10b1747547c3815e90d28166e92144835e065f
- git.kernel.org/stable/c/986d5fafb73b8b866651399934b66d690f49135a
- git.kernel.org/stable/c/8363c219d88e78daaee5665117a0380442989338
- git.kernel.org/stable/c/6eb6ebcc8590007ad59ddccc8b5f9201655b33f8
- git.kernel.org/stable/c/7958e67375aa111522086286bba13cfc0816ce8d
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON