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CVE-2026-80731— net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header

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.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于dev_validate_header()函数在处理CAP_SYS_RAWIO零填充时直接读取dev->hard_header_len，若设备重配置导致该值增大，可能引发缓冲区越界写入。

CVSS 7.8 · High EPSS 0.18% · P8

Affected Version Matrix 29

VendorProduct Version RangeStatus
Linux Linux b5518429e70cd783b8ca52335456172c1a0589f6< 53fd7f912c0877647d6a1e1877f5ea8535ee0b4a affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6 affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< 8fc9816404166a90ed8d544dc52482fafffb6d9f affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< b0f92a5731dc82556a9ae005cc35f71ab136307b affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< 99df6b7a713f96eda206680d100b76e15f9d9b69 affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< 74e035f07f53feca09e2352e77fccb09cad5e208 affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< dbb30dc943a93e083f1e531bfdc6779e57de40d0 affected
2793a23aacbd754dbbb5cb75093deb7e4103bace< fc902f52a02298c7432b2334c0c82a2885a1a8b6 affected
… +21 more rows
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I. Basic Information for CVE-2026-80731

Vulnerability Information
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Vulnerability Title
net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header dev_validate_header() reads dev->hard_header_len directly when zero-padding short link layer headers for CAP_SYS_RAWIO holders: if (capable(CAP_SYS_RAWIO)) { memset(ll_header + len, 0, dev->hard_header_len - len); return true; } Packet send paths call dev_validate_header() on skbs whose headroom was allocated from an earlier hard_header_len read. If the device is reconfigured so that dev->hard_header_len increases before validation, the memset writes past the reserved buffer, an out-of-bounds write. This out-of-bounds write is masked in some SOCK_RAW paths today because the same concurrent increase can first make skb_push() exceed the reserved headroom and trigger skb_under_panic(). Remove the zero-padding branch before making those hard_header_len reads consistent, so the snapshot fixes do not turn a loud panic into a silent overwrite. This path is only reached for variable length L2 protocols, where len < hard_header_len but len >= min_header_len. No remaining in-tree variable length L2 protocol implements header_ops->validate, and the CAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no real value beyond allowing testing of intentionally malformed input. Drop the CAP_SYS_RAWIO branch. The remaining reads of dev->hard_header_len in dev_validate_header() are comparisons only and have no memory safety impact.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于dev_validate_header()函数在处理CAP_SYS_RAWIO零填充时直接读取dev->hard_header_len，若设备重配置导致该值增大，可能引发缓冲区越界写入。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux b5518429e70cd783b8ca52335456172c1a0589f6 ~ 53fd7f912c0877647d6a1e1877f5ea8535ee0b4a -
Linux Linux 4.6 -

II. Public POCs for CVE-2026-80731

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III. Intelligence Information for CVE-2026-80731

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Patches & Fixes for CVE-2026-80731 (7)

Vendor Advisories for CVE-2026-80731 (1)

Other References for CVE-2026-80731 (1)

Same Patch Batch · Linux · 2026-09-03 · 32 CVEs total

CVE-2026-80726 9.3 CRITICAL KVM: x86/mmu: WARN and clear role.invalid when creating a child shadow page
CVE-2026-80734 8.8 HIGH btrfs: initialize inode mapping flags for cached inodes
CVE-2026-80745 8.4 HIGH regulator: fp9931: Fix VPOS/VNEG voltage selector table
CVE-2026-80750 8.4 HIGH pmdomain: mediatek: fix remaining %pOF after of_node_put()
CVE-2026-80752 8.4 HIGH Input: psxpad-spi - set driver data before use
CVE-2026-80753 8.4 HIGH ovpn: run deferred work on a module-owned workqueue
CVE-2026-80747 8.0 HIGH drm/amdkfd: Add bounds check for CRAT subtype length
CVE-2026-80751 7.8 HIGH pmdomain: mediatek: mfg: initialize prev_o in mtk_mfg_attach_dev()
CVE-2026-80754 7.8 HIGH Input: synaptics-rmi4 - fix F55 transmitter electrode count typo
CVE-2026-80748 7.8 HIGH mmc: loongson2: Fix sg iteration in data reorder functions
CVE-2026-80736 7.8 HIGH thunderbolt: Fix bandwidth group reservation indexing
CVE-2026-80737 7.8 HIGH serial: amba-pl011: synchronize DMA teardown
CVE-2026-80732 7.8 HIGH ata: pata_sl82c105: fix bridge revision use-after-free
CVE-2026-80735 7.3 HIGH ovpn: ensure socket is owned by ovpn before deref sk_user_data
CVE-2026-80738 7.3 HIGH bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie
CVE-2026-80741 7.1 HIGH drm/log: Fix out-of-bounds read on empty message length
CVE-2026-80749 7.1 HIGH drm/connector/hdmi: Fix out of bounds memory read
CVE-2026-80730 ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
CVE-2026-80733 net: remove WARN_ON_ONCE() from sk_mc_loop()
CVE-2026-80727 x86/mce: Set up the polling timer before CMCI discovery

Showing top 20 of 32 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-80731

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