CVE-2026-89493— Linux kernel 安全漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 2.6.32版本存在安全漏洞，该漏洞源于ocfs2的refcount块验证器未校验rl_used与rl_count，可能导致越界读取和越界内存移动，造成内存损坏，本地攻击者可通过挂载特制或损坏的ocfs2镜像触发。
可能的 ATT&CK 技术 1 AI
T1059 · Command and Scripting Interpreter影响版本矩阵 18
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< f882e9e32d017a6569b2996c63ba3864717788e6 |
affected |
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< 5593b63028cb43a6cda75a65ce1db95f00ea6857 |
affected | ||
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< c8b02f4ee91e757b3fff556c7168b24b7ae55132 |
affected | ||
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< 97584e93fc49a2d59252ac60467e9279f11b1b5b |
affected | ||
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< af56e90cb546cb0c47bef059335365283f61d6a4 |
affected | ||
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< 0761d2c9494424469a0d30a9da3496ca010b0b2d |
affected | ||
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< 04ead708e13ddcb9c39319cbe02a18cef99cb823 |
affected | ||
f2c870e3b12e38da6d9b5b17c4c8ae56a0ed68e4< 4ca62df6bc0708947b48da3f6a712ecb8e73929c |
affected | ||
| … +10 条更多 | |||
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一、 漏洞 CVE-2026-89493 基础信息
漏洞信息
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Vulnerability Title
ocfs2: validate rl_used against rl_count in refcount block validator
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
ocfs2: validate rl_used against rl_count in refcount block validator
ocfs2_find_refcount_rec_in_rl() walks the on-disk refcount record array
with:
for (; i < le16_to_cpu(rb->rf_records.rl_used); i++) {
rec = &rb->rf_records.rl_recs[i];
...
rl_recs[] lives in a single metadata block (4096 bytes on the common
configuration), so its real capacity is fixed by
ocfs2_refcount_recs_per_rb(sb) (247 records for a 4K block with the
16-byte ocfs2_refcount_rec). rl_used and rl_count are both read directly
off disk by ocfs2_validate_refcount_block() and are never checked against
that capacity, nor against each other, before any refcount/reflink/CoW
operation walks the array.
A crafted (or corrupted) refcount block with rl_used == 0xffff makes the
loop above walk far past the end of the block, dereferencing rl_recs[i]
for i up to 65534. The resulting index is then handed to the sibling
ocfs2_insert_refcount_rec(), whose insert-shift does:
if (index < le16_to_cpu(rf_list->rl_used))
memmove(&rf_list->rl_recs[index + 1],
&rf_list->rl_recs[index],
(le16_to_cpu(rf_list->rl_used) - index) *
sizeof(struct ocfs2_refcount_rec));
i.e. a memmove() of up to (0xffff - index) * 16 bytes (~1 MiB) from an
offset already past the block. This is reachable from an ordinary reflink
(FICLONE) against a crafted/corrupted ocfs2 image: attaching an extent
whose cpos sorts past every real record in the leaf forces the lookup to
run off the end instead of returning early on a match. The attacker model
is local: CAP_SYS_ADMIN mounting a crafted or corrupted ocfs2 image, or a
raw write to the block device backing an already-mounted ocfs2 filesystem.
ocfs2_validate_refcount_block() already validates the block's ECC,
signature, rf_blkno and rf_fs_generation, but never rl_count/rl_used
against the block's actual on-disk capacity. This is the same class of
gap that ocfs2_validate_extent_block() (fs/ocfs2/alloc.c) already closes
for the sibling extent-list header, which checks both the record capacity
and the "used" bound before any code walks h_list.l_recs[]:
if (le16_to_cpu(eb->h_list.l_count) != ocfs2_extent_recs_per_eb(sb)) {
rc = ocfs2_error(...);
goto bail;
}
if (le16_to_cpu(eb->h_list.l_next_free_rec) >
le16_to_cpu(eb->h_list.l_count)) {
rc = ocfs2_error(...);
goto bail;
}
Add the equivalent pair of checks to ocfs2_validate_refcount_block():
reject a refcount block whose rl_count does not match the fixed per-block
capacity returned by ocfs2_refcount_recs_per_rb(), and reject rl_used >
rl_count. Both checks are skipped when OCFS2_REFCOUNT_TREE_FL is set,
because in that case the same union bytes hold an ocfs2_extent_list
(rf_list), not the refcount record list (rf_records) -- that layout is
already validated separately by ocfs2_validate_extent_block() when the
referenced extent block is read. This mirrors the existing
"!(rb->rf_flags & OCFS2_REFCOUNT_TREE_FL)" guard used elsewhere in this
file (e.g. ocfs2_get_refcount_rec()) to decide whether rf_records or
rf_list is the live member of the union.
With this in place, a forged rl_used/rl_count is caught at block
validation time (ocfs2_error()), consistent with every other corruption
check in this function, instead of driving an out-of-bounds read in
ocfs2_find_refcount_rec_in_rl() and a subsequent out-of-bounds memmove()
in ocfs2_insert_refcount_rec().
Verified against a crafted image on a v6.19 KASAN (KASAN_GENERIC) build:
replaying the same reflink (FICLONE) reliably hit a KASAN report in
__ocfs2_increase_refcount()/ocfs2_insert_refcount_rec() before this patch,
and triggers no report once ocfs2_validate_refcount_block() rejects the
forged rl_used/rl_count.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel 2.6.32版本存在安全漏洞，该漏洞源于ocfs2的refcount块验证器未校验rl_used与rl_count，可能导致越界读取和越界内存移动，造成内存损坏，本地攻击者可通过挂载特制或损坏的ocfs2镜像触发。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD
受影响产品
二、漏洞 CVE-2026-89493 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2026-89493 补丁与修复 (8)
同批安全公告 · Linux · 2026-09-11 · 共 431 条
| CVE-2026-89688 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89656 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89655 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89658 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89660 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89659 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89662 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89669 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89674 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89675 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89676 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89677 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89681 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89686 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89703 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89479 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89478 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89702 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89482 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-89708 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
显示前 20 条，共 431 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-89493
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