Linux: Use After Free
CVE-2026-53401 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions a1a00f664a409b3412f9e1408c12890cffe50362, 5e10b1747547c3815e90d28166e92144835e065f, 986d5fafb73b8b866651399934b66d690f49135a as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to a1a00f664a409b3412f9e1408c12890cffe50362 or 5e10b1747547c3815e90d28166e92144835e065f or 986d5fafb73b8b866651399934b66d690f49135a or 8363c219d88e78daaee5665117a0380442989338, whichever matches your release line, or a later version.
- Update Linux Kernel to 7.1.3 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 078ff546a806b2c2ab74c25c8edd4c6d4680656a up to, but not including, a1a00f664a409b3412f9e1408c12890cffe50362; 078ff546a806b2c2ab74c25c8edd4c6d4680656a up to, but not including, 5e10b1747547c3815e90d28166e92144835e065f; 078ff546a806b2c2ab74c25c8edd4c6d4680656a up to, but not including, 986d5fafb73b8b866651399934b66d690f49135a; 078ff546a806b2c2ab74c25c8edd4c6d4680656a up to, but not including, 8363c219d88e78daaee5665117a0380442989338; 078ff546a806b2c2ab74c25c8edd4c6d4680656a up to, but not including, 6eb6ebcc8590007ad59ddccc8b5f9201655b33f8; 078ff546a806b2c2ab74c25c8edd4c6d4680656a up to, but not including, 7958e67375aa111522086286bba13cfc0816ce8d; 2.6.36 | a1a00f664a409b3412f9e1408c12890cffe50362, 5e10b1747547c3815e90d28166e92144835e065f, 986d5fafb73b8b866651399934b66d690f49135a, 8363c219d88e78daaee5665117a0380442989338, 6eb6ebcc8590007ad59ddccc8b5f9201655b33f8, 7958e67375aa111522086286bba13cfc0816ce8d |
| Linux | Linux Kernel | 2.6.36 up to, but not including, 7.1.3 | 7.1.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Use After Free vulnerabilities
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
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