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CVE-2026-80742— af_packet: Don't send zero-byte data in tpacket_snd().

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af_packet的tpacket_snd()函数在无hard header设备上通过TPACKET环形缓冲区发送0字节数据包时，未校验空skb长度，导致触发__dev_queue_xmit()中的skb_assert_len断言，可能造成拒绝服务。

AI Predicted 5.5 Difficulty: Moderate EPSS 0.21% · P12

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< dde212f8622f5cb36223fff1ebd6e6f2a3dc61fe affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 80a702964467b998d254f16cc61c2c9a20540c9d affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 7521e691c7c4f2231634c95053281ac888d1f452 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 1fc70b3d513bafb16b17540178870ef46e81c0bb affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 3fa110f9e2ea96f567f2194c673c4bc327640111 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 98c5914d6b7bd4b4675535908e57dea31f1efd6a affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< f09ac5682f1bb67981fcb6ead4d3cfe439225876 affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2< 6bcd76c134c55c697148acb5c0194e9666abdf84 affected
… +10 more rows
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I. Basic Information for CVE-2026-80742

Vulnerability Information
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Vulnerability Title
af_packet: Don't send zero-byte data in tpacket_snd().
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: af_packet: Don't send zero-byte data in tpacket_snd(). syzbot reported a WARNING in __dev_queue_xmit() triggered via tpacket_snd(): skb_assert_len WARNING: at include/linux/skbuff.h:2753 skb_assert_len WARNING: at __dev_queue_xmit+0x21bc/0x4970 net/core/dev.c:4781 Call Trace: <TASK> dev_queue_xmit include/linux/netdevice.h:3448 [inline] packet_xmit+0x243/0x310 net/packet/af_packet.c:276 tpacket_snd net/packet/af_packet.c:2907 [inline] packet_sendmsg+0x28d6/0x4eb0 net/packet/af_packet.c:3134 When sending 0-byte packets via TPACKET ring buffer on devices with no hard header (e.g. dev->hard_header_len == 0), tpacket_fill_skb() populates an skb with skb->len == 0 and returns 0. tpacket_snd() then forwards this empty skb to packet_xmit(), causing __dev_queue_xmit() to hit skb_assert_len(skb). Similar checks exist in packet_snd() via commit dc633700f00f ("net/af_packet: check len when min_header_len equals to 0") and in packet_sendmsg_spkt() via commit 6a341729fb31 ("af_packet: Don't send zero-byte data in packet_sendmsg_spkt()."). Return -EINVAL in tpacket_fill_skb() when skb->len is zero to reject zero-length packets in tpacket_snd().
Source: CVE Program / CVE List V5
CVSS Information
N/A
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af_packet的tpacket_snd()函数在无hard header设备上通过TPACKET环形缓冲区发送0字节数据包时，未校验空skb长度，导致触发__dev_queue_xmit()中的skb_assert_len断言，可能造成拒绝服务。
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 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ~ dde212f8622f5cb36223fff1ebd6e6f2a3dc61fe -
Linux Linux 2.6.12 -

II. Public POCs for CVE-2026-80742

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III. Intelligence Information for CVE-2026-80742

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Patches & Fixes for CVE-2026-80742 (7)

Other References for CVE-2026-80742 (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-2026-80753 8.4 HIGH ovpn: run deferred work on a module-owned workqueue
CVE-2026-80752 8.4 HIGH Input: psxpad-spi - set driver data before use
CVE-2026-80750 8.4 HIGH pmdomain: mediatek: fix remaining %pOF after of_node_put()
CVE-2026-80745 8.4 HIGH regulator: fp9931: Fix VPOS/VNEG voltage selector table
CVE-2026-80747 8.0 HIGH drm/amdkfd: Add bounds check for CRAT subtype length
CVE-2026-80754 7.8 HIGH Input: synaptics-rmi4 - fix F55 transmitter electrode count typo
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-2026-80731 7.8 HIGH net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header
CVE-2026-80736 7.8 HIGH thunderbolt: Fix bandwidth group reservation indexing
CVE-2026-80748 7.8 HIGH mmc: loongson2: Fix sg iteration in data reorder functions
CVE-2026-80751 7.8 HIGH pmdomain: mediatek: mfg: initialize prev_o in mtk_mfg_attach_dev()
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-2026-80749 7.1 HIGH drm/connector/hdmi: Fix out of bounds memory read
CVE-2026-80741 7.1 HIGH drm/log: Fix out-of-bounds read on empty message length
CVE-2026-80727 x86/mce: Set up the polling timer before CMCI discovery
CVE-2026-80740 drm/log: Fix infinite loop when scale is too large for display

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-2026-80742

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