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CVE-2026-80578— fbdev: core: Fix pointer desynchronization in fb_io_read()

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： fbdev: core: 修复 fb_io_read() 中的指针失步问题 在 函数中，当 执行部分拷贝（例如由于用户缓冲区故障）时，循环会调整块大小 并更新剩余的 。然而，硬件指针 已经按原始的块大小提前移动了。 如果允许循环继续执行，读取操作将从一个不正确、已过度前进的偏移量处恢复。由于剩余的 仅减少了成功拷贝的字节数，这种指针失步会导致后续迭代执行比原本限制更多的硬件读取，最终导致越界的 I/O 读取。 为此，在 发生部分拷贝时立即跳出循环。部分拷贝表明用户缓冲区

CVSS 7.3 · High EPSS 0.12% · P2

Affected Version Matrix 12

VendorProduct Version RangeStatus
Linux Linux 6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff< 42bc07b4e5a3c8a02a433388f562a8f46d093e11 affected
6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff< 42a6d8126c194133eafab2b0fd5c8668ebfcba5b affected
6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff< 7ff87a01ae3a8cd0208f7499386998223a8b5dba affected
6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff< 7110b7b794a2aac2c5cf8eb06ebf2af724c74d50 affected
6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff< 81cc73be40c6f028f1ee3f438ace46afe666dbae affected
6.5 affected
< 6.5 unaffected
6.6.153≤ 6.6.* unaffected
… +4 more rows
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I. Basic Information for CVE-2026-80578

Vulnerability Information
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Vulnerability Title
fbdev: core: Fix pointer desynchronization in fb_io_read()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: core: Fix pointer desynchronization in fb_io_read() In fb_io_read(), if copy_to_user() performs a partial copy (e.g., due to a faulty user buffer), the loop adjusts the chunk size 'c' and updates the remaining 'count'. However, the hardware 'src' pointer has already been eagerly advanced by the original chunk size. If the loop is allowed to continue, the read will resume from an incorrect, over-advanced offset. Since the remaining 'count' was only decremented by the successful bytes, this desynchronization causes the next iterations to execute more hardware reads than originally bounded, eventually leading to out-of-bounds I/O reads. Fix this by breaking out of the loop immediately upon a partial copy_to_user(). A partial copy indicates a faulty user buffer, making subsequent read attempts futile. Breaking out ensures we return the number of successfully read bytes without risking out-of-bounds hardware accesses in subsequent mismatched iterations.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/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 6121cd9ef911432b14c2a17aefaf8cd2f3cfcdff ~ 42bc07b4e5a3c8a02a433388f562a8f46d093e11 -
Linux Linux 6.5 -

II. Public POCs for CVE-2026-80578

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III. Intelligence Information for CVE-2026-80578

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Patches & Fixes for CVE-2026-80578 (4)

Other References for CVE-2026-80578 (1)

Same Patch Batch · Linux · 2026-08-26 · 92 CVEs total

CVE-2026-80519 9.8 CRITICAL ovpn: finish crypto callback cleanup before peer release
CVE-2026-74743 9.8 CRITICAL macvlan: inherit needed_headroom and needed_tailroom from lowerdev
CVE-2026-74737 9.8 CRITICAL net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG
CVE-2026-80586 9.8 CRITICAL mptcp: options: reset DSS fields in case of unexpected size
CVE-2026-80587 9.8 CRITICAL mptcp: avoid combining some incoming suboptions
CVE-2026-74744 9.8 CRITICAL ipvlan: inherit needed_headroom and needed_tailroom from phy_dev
CVE-2026-74746 9.8 CRITICAL netfilter: flowtable: publish GC-visible tuple last
CVE-2026-80557 9.8 CRITICAL libceph: fix OOB read in decode_watchers() via missing bounds check
CVE-2026-80558 9.8 CRITICAL libceph: Avoid using invalid osd indices from primary_temp
CVE-2026-80561 9.8 CRITICAL libceph: fix multiple unsafe decodes in decode_locker()
CVE-2026-80528 9.8 CRITICAL ceph: avoid fs reclaim while using current->journal_info
CVE-2026-74752 9.8 CRITICAL sctp: validate cookie AUTH state before use
CVE-2026-80589 9.8 CRITICAL block: stop the timeout timer when releasing a never added disk
CVE-2026-74751 9.4 CRITICAL riscv: lib: Fix ZBB strnlen reading past count boundary
CVE-2026-80585 9.4 CRITICAL mptcp: fastopen: only mark MPTFO subflows with SYN data
CVE-2026-80551 9.3 CRITICAL s390/vfio_ccw: Ensure first IDAW remains constant
CVE-2026-80554 9.3 CRITICAL s390/vfio_ccw: Limit the number of channel program segments
CVE-2026-80553 8.8 HIGH s390/vfio_ccw: Cancel existing workqueues
CVE-2026-80552 8.8 HIGH s390/vfio_ccw: Ensure index for read/write regions are within range
CVE-2026-80576 8.8 HIGH drm/amdgpu: reject oversized IBs with per-ring packet limits

Showing top 20 of 92 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-80578

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