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CVE-2026-74582

packet: use consistent hard_header_len in non-ring send paths

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.5, 4.10, 4.15, 4.17, 5.10.267, and 6 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in bcd4df60ac9481b1ceffdfe5ec38fe51dcaae812; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in 78a47127e33c340bc6d38dcc4552a094b4f5cc77; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in 142e287b3a25cfe909215177c23243e7fc5ae2b1; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in 91f041451f967cd87ed722a8f43c0b767a64f1a0; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in 9052756290962ffb9a661bcf319e92dedaaedfed; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in 5bb10753d428aadfc356a2bfe9acea09c82a62ec; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in b06b6fce6d7deaf7238e09b48ce3b1125ff41acd; From b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba · fixed in 03390aa32e669cc4ecd7d34108e2e1afc13d689d; From 4.4.133 · fixed in 4.5; From 4.9.103 · fixed in 4.10; From 4.14.44 · fixed in 4.15; From 4.16.12 · fixed in 4.17

  • Linux Linux

    4.17

  • KernelLinux

    From 4.17.0 · fixed in 5.10.267; From 5.11.0 · fixed in 5.15.218; From 5.16.0 · fixed in 6.1.185; From 6.2.0 · fixed in 6.6.152; From 6.7.0 · fixed in 6.12.104; From 6.13.0 · fixed in 6.18.45; From 6.19.0 · fixed in 7.1.9

References 8

git.kernel.org