CVE-2026-80742
af_packet: Don't send zero-byte data in tpacket_snd().
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().
INFO
Published Date :
Sept. 3, 2026, 1:06 p.m.
Last Modified :
Sept. 3, 2026, 1:06 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update the Linux kernel to the latest version.
- Apply specific patches for af_packet vulnerability.
- Ensure devices have a hard header length.
- Validate packet lengths before sending.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-80742.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-80742 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-80742
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-80742 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-80742 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Sep. 03, 2026
Action Type Old Value New Value Added 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(). Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80742.json">CVE-2026-80742</a> Added Reference https://git.kernel.org/stable/c/1fc70b3d513bafb16b17540178870ef46e81c0bb Added Reference https://git.kernel.org/stable/c/3fa110f9e2ea96f567f2194c673c4bc327640111 Added Reference https://git.kernel.org/stable/c/6bcd76c134c55c697148acb5c0194e9666abdf84 Added Reference https://git.kernel.org/stable/c/7521e691c7c4f2231634c95053281ac888d1f452 Added Reference https://git.kernel.org/stable/c/80a702964467b998d254f16cc61c2c9a20540c9d Added Reference https://git.kernel.org/stable/c/98c5914d6b7bd4b4675535908e57dea31f1efd6a Added Reference https://git.kernel.org/stable/c/dde212f8622f5cb36223fff1ebd6e6f2a3dc61fe Added Reference https://git.kernel.org/stable/c/f09ac5682f1bb67981fcb6ead4d3cfe439225876