CVE-2025-21709kernel: be more careful about dup_mmap() failures and uprobe registering
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: kernel: be more careful about dup_mmap() failures and uprobe registering If a memory allocation fails during dup_mmap(), the maple tree can be left in an unsafe state for other iterators besides the exit path. All the locks are dropped before the exit_mmap() call (in mm/mmap.c), but the incomplete mm_struct can be reached through (at least) the rmap finding the vmas which have a pointer back to the mm_struct. Up to this point, there have been no issues with being able to find an mm_struct that was only partially initialised. Syzbot was able to make the incomplete mm_struct fail with recent forking changes, so it has been proven unsafe to use the mm_struct that hasn't been initialised, as referenced in the link below. Although 8ac662f5da19f ("fork: avoid inappropriate uprobe access to invalid mm") fixed the uprobe access, it does not completely remove the race. This patch sets the MMF_OOM_SKIP to avoid the iteration of the vmas on the oom side (even though this is extremely unlikely to be selected as an oom victim in the race window), and sets MMF_UNSTABLE to avoid other potential users from using a partially initialised mm_struct. When registering vmas for uprobe, skip the vmas in an mm that is marked unstable. Modifying a vma in an unstable mm may cause issues if the mm isn't fully initialised.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from d2406291483775ecddaee929231a39c70c08fda2 before 74c2471eb891a7dcb3874b21c106cda75f52be30; from d2406291483775ecddaee929231a39c70c08fda2 before da139948aeda677ac09cc0e7d837f8a314de7d55; from d2406291483775ecddaee929231a39c70c08fda2 before 64c37e134b120fb462fb4a80694bfb8e7be77b14 | CNA record |
linux linux_kernel linux:linux_kernel | from 6.8 before 6.13.2 | NVD |
References
- https://git.kernel.org/stable/c/74c2471eb891a7dcb3874b21c106cda75f52be30
- https://git.kernel.org/stable/c/da139948aeda677ac09cc0e7d837f8a314de7d55patch
- https://git.kernel.org/stable/c/64c37e134b120fb462fb4a80694bfb8e7be77b14patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.