CVE-2023-53026 RDMA/core: Fix ib block iterator counter overflow
An integer overflow in the Linux kernel RDMA core allows a local attacker to cause an infinite loop and system denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53026?
CVE-2023-53026 is a high-severity vulnerability in Linux kernel, published on 27 Mar 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
RDMA/core: Fix ib block iterator counter overflow
When registering a new DMA MR after selecting the best aligned page size for it, we iterate over the given sglist to split each entry to smaller, aligned to the selected page size, DMA blocks.
In given circumstances where the sg entry and page size fit certain sizes and the sg entry is not aligned to the selected page size, the total size of the aligned pages we need to cover the sg entry is >= 4GB. Under this circumstances, while iterating page aligned blocks, the counter responsible for counting how much we advanced from the start of the sg entry is overflowed because its type is u32 and we pass 4GB in size. This can lead to an infinite loop inside the iterator function because the overflow prevents the counter to be larger than the size of the sg entry.
Fix the presented problem by changing the advancement condition to eliminate overflow.
Backtrace: [ 192.374329] efa_reg_user_mr_dmabuf [ 192.376783] efa_register_mr [ 192.382579] pgsz_bitmap 0xfffff000 rounddown 0x80000000 [ 192.386423] pg_sz [0x80000000] umem_length[0xc0000000] [ 192.392657] start 0x0 length 0xc0000000 params.page_shift 31 params.page_num 3 [ 192.399559] hp_cnt[3], pages_in_hp[524288] [ 192.403690] umem->sgt_append.sgt.nents[1] [ 192.407905] number entries: [1], pg_bit: [31] [ 192.411397] biter->__sg_nents [1] biter->__sg [0000000008b0c5d8] [ 192.415601] biter->__sg_advance [665837568] sg_dma_len[3221225472] [ 192.419823] biter->__sg_nents [1] biter->__sg [0000000008b0c5d8] [ 192.423976] biter->__sg_advance [2813321216] sg_dma_len[3221225472] [ 192.428243] biter->__sg_nents [1] biter->__sg [0000000008b0c5d8] [ 192.432397] biter->__sg_advance [665837568] sg_dma_len[3221225472]
Weakness: CWE-835
Which versions are affected by CVE-2023-53026?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53026?
Apply the vendor's patch.
Is CVE-2023-53026 being exploited?
There is no known exploitation of CVE-2023-53026 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53026, DEBIAN-CVE-2023-53026, GHSA-gr26-qx48-q4hh, UBUNTU-CVE-2023-53026.