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Fencer Vulns
no cvss —

CVE-2026-89496 json

ocfs2: always run deallocs on copy-on-write completion

published 2026-09-11 58 d ago modified 2026-10-19 21 d ago also EUVD-2026-76402

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: always run deallocs on copy-on-write completion

Local fuzzing of 6.12.94 has found the following memory leak caused by doing 'copy_file_range()' within the same filesystem:

unreferenced object 0xffff88812192c980 (size 32): comm "syz.0.49", pid 12095, jiffies 4294964143 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 00 00 00 00 00 00 00 ................ c0 c5 92 21 81 88 ff ff 00 02 00 00 00 06 00 00 ...!............ backtrace (crc 7068d63f): kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline] slab_post_alloc_hook mm/slub.c:4152 [inline] slab_alloc_node mm/slub.c:4197 [inline] __kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358 kmalloc_noprof include/linux/slab.h:878 [inline] ocfs2_find_per_slot_free_list fs/ocfs2/alloc.c:6618 [inline] ocfs2_cache_block_dealloc+0x155/0x4b0 fs/ocfs2/alloc.c:6786 ocfs2_cache_extent_block_free fs/ocfs2/alloc.c:6819 [inline] ocfs2_unlink_path+0x286/0x450 fs/ocfs2/alloc.c:2613 ocfs2_rotate_subtree_left fs/ocfs2/alloc.c:2779 [inline] __ocfs2_rotate_tree_left+0x1f6f/0x2da0 fs/ocfs2/alloc.c:2985 ocfs2_rotate_tree_left+0x283/0xe00 fs/ocfs2/alloc.c:3237 ocfs2_try_to_merge_extent+0xf56/0x1a20 fs/ocfs2/alloc.c:3825 ocfs2_split_extent+0x15f4/0x2940 fs/ocfs2/alloc.c:5138 ocfs2_clear_ext_refcount+0x2f6/0x550 fs/ocfs2/refcounttree.c:3098 ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3131 [inline] ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3255 [inline] ocfs2_replace_cow+0x991/0x1660 fs/ocfs2/refcounttree.c:3349 ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3427 [inline] ocfs2_refcount_cow+0x5e1/0x9f0 fs/ocfs2/refcounttree.c:3470 ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2340 [inline] ocfs2_file_write_iter+0xbda/0x1880 fs/ocfs2/file.c:2451 iter_file_splice_write+0x890/0xf60 fs/splice.c:743 do_splice_from fs/splice.c:944 [inline] direct_splice_actor+0x232/0x480 fs/splice.c:1167 splice_direct_to_actor+0x4b4/0xb60 fs/splice.c:1111 do_splice_direct_actor fs/splice.c:1210 [inline] do_splice_direct+0x10f/0x1c0 fs/splice.c:1236 do_sendfile+0x430/0xbf0 fs/read_write.c:1388

unreferenced object 0xffff88812192c5c0 (size 32): comm "syz.0.49", pid 12095, jiffies 4294964143 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 29 70 00 00 00 00 00 00 19 00 00 00 00 00 00 00 )p.............. backtrace (crc afec850f): kmemleak_alloc_recursive include/linux/kmemleak.h:42 [inline] slab_post_alloc_hook mm/slub.c:4152 [inline] slab_alloc_node mm/slub.c:4197 [inline] __kmalloc_cache_noprof+0x168/0x2c0 mm/slub.c:4358 kmalloc_noprof include/linux/slab.h:878 [inline] kzalloc_noprof include/linux/slab.h:1014 [inline] ocfs2_cache_block_dealloc+0x25c/0x4b0 fs/ocfs2/alloc.c:6793 ocfs2_cache_extent_block_free fs/ocfs2/alloc.c:6819 [inline] ocfs2_unlink_path+0x286/0x450 fs/ocfs2/alloc.c:2613 ocfs2_rotate_subtree_left fs/ocfs2/alloc.c:2779 [inline] __ocfs2_rotate_tree_left+0x1f6f/0x2da0 fs/ocfs2/alloc.c:2985 ocfs2_rotate_tree_left+0x283/0xe00 fs/ocfs2/alloc.c:3237 ocfs2_try_to_merge_extent+0xf56/0x1a20 fs/ocfs2/alloc.c:3825 ocfs2_split_extent+0x15f4/0x2940 fs/ocfs2/alloc.c:5138 ocfs2_clear_ext_refcount+0x2f6/0x550 fs/ocfs2/refcounttree.c:3098 ocfs2_replace_clusters fs/ocfs2/refcounttree.c:3131 [inline] ocfs2_make_clusters_writable fs/ocfs2/refcounttree.c:3255 [inline] ocfs2_replace_cow+0x991/0x1660 fs/ocfs2/refcounttree.c:3349 ocfs2_refcount_cow_hunk fs/ocfs2/refcounttree.c:3427 [inline] ocfs2_refcount_cow+0x5e1/0x9f0 fs/ocfs2/refcounttree.c:3470 ocfs2_prepare_inode_for_write fs/ocfs2/file.c:2340 [inline] ocfs2_file_write_iter+0xbda/0x1880 fs/ocfs2/file.c:2451 iter_file_splice_write+0x890/0xf60 fs/splice.c:743 do_splice_from fs/splice.c:9 ---truncated---

Patch / fix

  • Linux Linux 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
  • linux Debian 12 6.1.190-1
  • linux Debian 13 6.12.111-1
  • linux Debian 14 7.2.6-1
  • linux-6.12 Debian 12 6.12.111-1~deb12u1

debian advisories DEBIAN-CVE-2026-89496

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-89496

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.2.7-1.1

opensuse advisories openSUSE-SU-2026:11880-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89496 updated cvss 5.5

kernel: ocfs2: always run deallocs on copy-on-write completion

  • Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.