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5.5
CVE-2026-53047: Linux Kernel: Incorrect Allocation Size in EFI Capsule Loader
CVE-2026-53047
Summary
A bug in the Linux kernel's EFI capsule loader could cause a heap buffer overflow on 32-bit systems. This issue occurs when storing physical addresses, which might lead to system instability or crashes. Update your Linux kernel to fix this issue.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| linux | linux_kernel |
>= 4.14.13, < 4.15 >= 4.15.1, < 5.10.258 >= 5.11, < 5.15.209 >= 5.16, < 6.1.175 >= 6.2, < 6.6.141 >= 6.7, < 6.12.91 >= 6.13, < 6.18.33 >= 6.19, < 7.0.10 4.15 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
Original title
In the Linux kernel, the following vulnerability has been resolved:
efi/capsule-loader: fix incorrect sizeof in phys array reallocation
The krealloc() call for cap_info->phys in __efi_capsule_set...
Original description
In the Linux kernel, the following vulnerability has been resolved:
efi/capsule-loader: fix incorrect sizeof in phys array reallocation
The krealloc() call for cap_info->phys in __efi_capsule_setup_info() uses
sizeof(phys_addr_t *) instead of sizeof(phys_addr_t), which might be
causing an undersized allocation.
The allocation is also inconsistent with the initial array allocation in
efi_capsule_open() that allocates one entry with sizeof(phys_addr_t),
and the efi_capsule_write() function that stores phys_addr_t values (not
pointers) via page_to_phys().
On 64-bit systems where sizeof(phys_addr_t) == sizeof(phys_addr_t *), this
goes unnoticed. On 32-bit systems with PAE where phys_addr_t is 64-bit but
pointers are 32-bit, this allocates half the required space, which might
lead to a heap buffer overflow when storing physical addresses.
This is similar to the bug fixed in commit fccfa646ef36 ("efi/capsule-loader:
fix incorrect allocation size") which fixed the same issue at the initial
allocation site.
efi/capsule-loader: fix incorrect sizeof in phys array reallocation
The krealloc() call for cap_info->phys in __efi_capsule_setup_info() uses
sizeof(phys_addr_t *) instead of sizeof(phys_addr_t), which might be
causing an undersized allocation.
The allocation is also inconsistent with the initial array allocation in
efi_capsule_open() that allocates one entry with sizeof(phys_addr_t),
and the efi_capsule_write() function that stores phys_addr_t values (not
pointers) via page_to_phys().
On 64-bit systems where sizeof(phys_addr_t) == sizeof(phys_addr_t *), this
goes unnoticed. On 32-bit systems with PAE where phys_addr_t is 64-bit but
pointers are 32-bit, this allocates half the required space, which might
lead to a heap buffer overflow when storing physical addresses.
This is similar to the bug fixed in commit fccfa646ef36 ("efi/capsule-loader:
fix incorrect allocation size") which fixed the same issue at the initial
allocation site.
- https://git.kernel.org/stable/c/22022cd8851703a58f67615a17bc7e9e8682785b
- https://git.kernel.org/stable/c/48a428215782321b56956974f23593e40ce84b7a
- https://git.kernel.org/stable/c/5e185330d902b12fe8e6eb4b8514b5d736d8d66d
- https://git.kernel.org/stable/c/608e1f7bc9d171ab26c1fba288c97fc76363c27d
- https://git.kernel.org/stable/c/67adde6bfdfd563a54b045d59aeb9a2d90c80697
- https://git.kernel.org/stable/c/8be69e9245f805566bac68ffc8574b64735fd996
- https://git.kernel.org/stable/c/ab3f7098a3a27175b91cfc947950f5c26855801b
- https://git.kernel.org/stable/c/e0e6b14995fd6fa2c0df8c712d76ab32f0694c31
Published: 24 Jun 2026 · Updated: 21 Jul 2026 · First seen: 14 Jul 2026