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CVE-2026-90203— Squashfs: check block offset is not negative

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，以下漏洞已得到修复： Squashfs：检查块偏移量是否为负数 如果从磁盘上读取到一个负数的偏移量（例如，指向解压后的 fragment 块的偏移量），这将导致 执行越界访问。 修复方法是检查偏移量是否为负数，如果是则返回 0。这与现有行为保持一致，即当偏移量超出块范围时，返回 0 字节被复制。 要触发此越界访问，需要构造一个特殊的 Squashfs 文件系统，并且需要 权限来挂载它。非特权用户无法挂载这样的文件系统，但一旦文件系统被挂载，非特权用户可以通过读取带有负偏移量的特制文件来触发该

CVSS 7.1 · High EPSS 0.18% · P7

Possible ATT&CK Techniques 2 AI

T1079 T1562

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux f400e12656ab518be107febfe2315fb1eab5a342< b169185d5c672b989985c6c2e38cafab2548ba88 affected
f400e12656ab518be107febfe2315fb1eab5a342< c2a126fca820ae74872da28de68dc74d4595dc4b affected
f400e12656ab518be107febfe2315fb1eab5a342< 95dadf366c117dcdca78a570e6832071deab1ecd affected
f400e12656ab518be107febfe2315fb1eab5a342< 3d2f0cb66c909ea2312cdef465165bb9a3ba2d84 affected
f400e12656ab518be107febfe2315fb1eab5a342< bbb2218eb072b0a15dc063929200183bd23c2344 affected
f400e12656ab518be107febfe2315fb1eab5a342< d0a3729d464fcf516416a41cf304c0c92126ee03 affected
f400e12656ab518be107febfe2315fb1eab5a342< e4afd90bc7bf3dd477970c6c42bdd29ad3fda7fe affected
f400e12656ab518be107febfe2315fb1eab5a342< e300eb5002925b29be803d2661af07266cfa267e affected
… +10 more rows
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I. Basic Information for CVE-2026-90203

Vulnerability Information
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Vulnerability Title
Squashfs: check block offset is not negative
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: Squashfs: check block offset is not negative If a negative offset is read off disk (for example the offset into the decompressed fragment block), this will cause squashfs_copy_data() to perform an out of bounds access. Fix by checking if offset is negative, and returning 0. This matches existing behaviour where an offset beyond the block returns 0 bytes copied. To trigger this out of bounds access requires a crafted Squashfs filesystem and CAP_SYS_ADMIN to mount it. Unprivileged users will not be able to mount such a filesystem, but once mounted, an unprivileged user can trigger the out of bounds access by reading the crafted file with the negative offset.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux f400e12656ab518be107febfe2315fb1eab5a342 ~ b169185d5c672b989985c6c2e38cafab2548ba88 -
Linux Linux 2.6.29 -

II. Public POCs for CVE-2026-90203

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III. Intelligence Information for CVE-2026-90203

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Patches & Fixes for CVE-2026-90203 (8)

Same Patch Batch · Linux · 2026-09-17 · 600 CVEs total

CVE-2026-92489 9.8 CRITICAL xfrm: Fix skb double-free in xfrm_dev_direct_output()
CVE-2026-90104 9.8 CRITICAL NFSv4.1: zero referring call lists before decoding
CVE-2026-90235 9.8 CRITICAL sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE
CVE-2026-90173 9.8 CRITICAL smb: smbdirect: free completion queues with ib_free_cq()
CVE-2026-90151 9.8 CRITICAL NFSv4: remove callback IDR entry on client allocation failure
CVE-2026-90110 9.4 CRITICAL inetpeer: randomize RB-tree node comparison using SipHash
CVE-2026-90413 9.1 CRITICAL IB/isert: reject login PDUs declaring more data than was received
CVE-2026-90414 9.1 CRITICAL IB/isert: reject PDUs declaring more data than was received
CVE-2026-90230 9.1 CRITICAL nvmet: fix heap out-of-bounds read in nvmet_auth_negotiate()
CVE-2026-90256 8.8 HIGH Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind
CVE-2026-90357 8.8 HIGH wifi: mt76: mt7915: unlink TWT flow if the MCU rejects the agreement
CVE-2026-90286 8.8 HIGH drm/amdgpu/gfx6: Use PFP on the compute queues too
CVE-2026-90381 8.8 HIGH wifi: mt76: fix handling channel context with different bands in mt76_switch_vif_chanctx()
CVE-2026-90380 8.8 HIGH wifi: mt76: mt792x: fix use-after-free in mt76_rx_poll_complete
CVE-2026-90329 8.8 HIGH HID: synchronize input before cleaning up a failed probe
CVE-2026-93042 8.8 HIGH dmaengine: dw-edma: Terminate all descriptors without callbacks
CVE-2026-90162 8.8 HIGH ksmbd: defer publishing granted locks to prevent UAF/double-free race
CVE-2026-90379 8.8 HIGH wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash
CVE-2026-90367 8.8 HIGH wifi: mt76: mt7996: hold dev->mt76.mutex while disabling tx worker in SER
CVE-2026-90371 8.8 HIGH wifi: mt76: fix RXDMAD_C buffer recycling race

Showing top 20 of 600 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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