medium CVSS 5.5 EPSS <0.1%

CVE-2023-52739·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: Fix page corruption caused by racy check in __free_pages When we upgraded our kernel, we started seeing some page corruption like the following consistently: BUG: Bad page state in process ganesha.nfsd pfn:1304ca page:0000000022261c55 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1304ca flags: 0x17ffffc0000000() raw: 0017ffffc0000000 ffff8a513ffd4c98 ffffeee24b35ec08 0000000000000000 raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000 page dumped because: nonzero mapcount CPU: 0 PID: 15567 Comm: ganesha.nfsd Kdump: loaded Tainted: P B O 5.10.158-1.nutanix.20221209.el7.x86_64 #1 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016 Call Trace: dump_stack+0x74/0x96 bad_page.cold+0x63/0x94 check_new_page_bad+0x6d/0x80 rmqueue+0x46e/0x970 get_page_from_freelist+0xcb/0x3f0 ? _cond_resched+0x19/0x40 __alloc_pages_nodemask+0x164/0x300 alloc_pages_current+0x87/0xf0 skb_page_frag_refill+0x84/0x110 ... Sometimes, it would also show up as corruption in the free list pointer and cause crashes. After bisecting the issue, we found the issue started from commit e320d3012d25 ("mm/page_alloc.c: fix freeing non-compound pages"): if (put_page_testzero(page)) free_the_page(page, order); else if (!PageHead(page)) while (order-- > 0) free_the_page(page + (1 << order), order); So the problem is the check PageHead is racy because at this point we already dropped our reference to the page. So even if we came in with compound page, the page can already be freed and PageHead can return false and we will end up freeing all the tail pages causing double free.

Severity
medium
Software
Kernel
Fixed in
6.1.12
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 4% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Affected versions

From: 5.16

Until: 6.1.12

Fixed in: 6.1.12

How to fix this CVE

Update your Linux kernel to version 6.1.12 or later to resolve a critical memory management race condition that causes page corruption. This vulnerability affects kernel versions 5.16 through 6.1.11 and can lead to data corruption and system instability. Apply the patch immediately through your distribution's package manager.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check your current kernel version: uname -r
  2. Verify if you are running a vulnerable version between 5.16 and 6.1.11: if [[ $(uname -r | cut -d. -f1,2) == '5.16' ]] || [[ $(uname -r | cut -d. -f1,2) == '6.0' ]] || [[ $(uname -r | cut -d. -f1,2) == '6.1' && $(uname -r | cut -d. -f3) -lt 12 ]]; then echo 'VULNERABLE'; fi
  3. Search kernel logs for page corruption warnings: sudo dmesg | grep -i 'bad page state\|nonzero mapcount\|page corruption'
  4. Verify the patch has been applied by checking if the kernel version is 6.1.12 or later: uname -r | awk -F. '{if ($1 > 6 || ($1 == 6 && $2 > 1) || ($1 == 6 && $2 == 1 && $3 >= 12)) print "PATCHED"; else print "VULNERABLE"}'

FAQ

What is CVE-2023-52739?

This vulnerability is a race condition in the Linux kernel's page memory management subsystem that occurs during page deallocation. When a compound page is freed, a timing window allows the kernel to incorrectly identify it as a non-compound page, leading to double-free corruption of tail pages and potential system instability.

Is CVE-2023-52739 being actively exploited?

No, CVE-2023-52739 is not listed on the CISA Known Exploited Vulnerabilities catalog and has no publicly available exploits. However, it can be triggered through normal kernel memory operations under load.

What versions of Kernel are affected by CVE-2023-52739?

Linux kernel versions 5.16 through 6.1.11 are vulnerable. The vulnerability was introduced in commit e320d3012d25 and fixed in kernel 6.1.12.

How do I check if my server is vulnerable to CVE-2023-52739?

Run 'uname -r' to check your kernel version. If the output shows version 5.16.x, 6.0.x, or 6.1.x (where x is less than 12), your system is vulnerable and requires an update.

Does Defensia detect CVE-2023-52739?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2023-52739 will appear in your dashboard with remediation steps.

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CVE-2026-46325CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE The current implementation incorrectly handles memory regions (MRs) with page sizes different from the system PAGE_SIZE. The core issue is that rxe_set_page() is called with mr->page_size step increments, but the page_list stores individual struct page pointers, each representing PAGE_SIZE of memory. ib_sg_to_page() has ensured that when i>=1 either a) SG[i-1].dma_end and SG[i].dma_addr are contiguous or b) SG[i-1].dma_end and SG[i].dma_addr are mr->page_size aligned. This leads to incorrect iova-to-va conversion in scenarios: 1) page_size < PAGE_SIZE (e.g., MR: 4K, system: 64K): ibmr->iova = 0x181800 sg[0]: dma_addr=0x181800, len=0x800 sg[1]: dma_addr=0x173000, len=0x1000 Access iova = 0x181800 + 0x810 = 0x182010 Expected VA: 0x173010 (second SG, offset 0x10) Before fix: - index = (0x182010 >> 12) - (0x181800 >> 12) = 1 - page_offset = 0x182010 & 0xFFF = 0x10 - xarray[1] stores system page base 0x170000 - Resulting VA: 0x170000 + 0x10 = 0x170010 (wrong) 2) page_size > PAGE_SIZE (e.g., MR: 64K, system: 4K): ibmr->iova = 0x18f800 sg[0]: dma_addr=0x18f800, len=0x800 sg[1]: dma_addr=0x170000, len=0x1000 Access iova = 0x18f800 + 0x810 = 0x190010 Expected VA: 0x170010 (second SG, offset 0x10) Before fix: - index = (0x190010 >> 16) - (0x18f800 >> 16) = 1 - page_offset = 0x190010 & 0xFFFF = 0x10 - xarray[1] stores system page for dma_addr 0x170000 - Resulting VA: system page of 0x170000 + 0x10 = 0x170010 (wrong) Yi Zhang reported a kernel panic[1] years ago related to this defect. Solution: 1. Replace xarray with pre-allocated rxe_mr_page array for sequential indexing (all MR page indices are contiguous) 2. Each rxe_mr_page stores both struct page* and offset within the system page 3. Handle MR page_size != PAGE_SIZE relationships: - page_size > PAGE_SIZE: Split MR pages into multiple system pages - page_size <= PAGE_SIZE: Store offset within system page 4. Add boundary checks and compatibility validation This ensures correct iova-to-va conversion regardless of MR page size and system PAGE_SIZE relationship, while improving performance through array-based sequential access. Tests on 4K and 64K PAGE_SIZE hosts: - rdma-core/pytests $ ./build/bin/run_tests.py --dev eth0_rxe - blktest: $ TIMEOUT=30 QUICK_RUN=1 USE_RXE=1 NVMET_TRTYPES=rdma ./check nvme srp rnbd [1] https://lore.kernel.org/all/CAHj4cs9XRqE25jyVw9rj9YugffLn5+f=1znaBEnu1usLOciD+g@mail.gmail.com/T/
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References

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