CVE Catalog

CVE-2026-74582

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.12%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel, the packet_snd() function (packet send path) has an inconsistency in reading dev->hard_header_len, which can lead to an out-of-bounds write during skb construction. The issue also affects packet_sendmsg_spkt().

Risk Assessment

Risk of out-of-bounds memory write, potentially leading to system crash or potential kernel code execution.

Recommendation

Apply the Linux kernel patch that reads hard_header_len once and uses a consistent value throughout the send path.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: packet: use consistent hard_header_len in non-ring send paths packet_snd() reads dev->hard_header_len multiple times while allocating and constructing an skb. Device reconfiguration can change this value concurrently, for example through bonding device type changes. For SOCK_RAW, packet_snd() can save a larger value in reserve and later allocate headroom using a smaller value. Moving skb->data back by reserve then places it before skb->head, and the following copy from userspace can attempt an out-of-bounds write. packet_sendmsg_spkt() has the same issue because it calculates its reservation and header offset from separate reads before dropping the RCU read lock to allocate the skb. Add LL_RESERVED_SPACE_EX() for callers that already saved a header length. Read hard_header_len once in packet_snd() and use it for allocation and construction. In packet_sendmsg_spkt(), preserve the allocation-time value through the device lookup retry. The separate SOCK_DGRAM consistency problem between hard_header_len and header_ops->create is not addressed here.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS