CVE-2026-74582
Description
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.
How to fix
- Linux Linuxbcd4df60ac9481b1ceffdfe5ec38fe51dcaae812, 78a47127e33c340bc6d38dcc4552a094b4f5cc77, 142e287b3a25cfe909215177c23243e7fc5ae2b1, 91f041451f967cd87ed722a8f43c0b767a64f1a0, 9052756290962ffb9a661bcf319e92dedaaedfed, 5bb10753d428aadfc356a2bfe9acea09c82a62ec, b06b6fce6d7deaf7238e09b48ce3b1125ff41acd, 03390aa32e669cc4ecd7d34108e2e1afc13d689d, 4.5, 4.10, 4.15, 4.17 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < bcd4df60ac9481b1ceffdfe5ec38fe51dcaae812, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < 78a47127e33c340bc6d38dcc4552a094b4f5cc77, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < 142e287b3a25cfe909215177c23243e7fc5ae2b1, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < 91f041451f967cd87ed722a8f43c0b767a64f1a0, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < 9052756290962ffb9a661bcf319e92dedaaedfed, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < 5bb10753d428aadfc356a2bfe9acea09c82a62ec, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < b06b6fce6d7deaf7238e09b48ce3b1125ff41acd, b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ≤ v < 03390aa32e669cc4ecd7d34108e2e1afc13d689d, d9fb8cc230b2a4757e9fe4f81468f81212d4deaa, 6190cce26e40bf71c4d375b21eea74bb07b6a0f3, 01a658c1b9d4b5393c38d5a92d9112ab1425382a, 8809ae6747e760e6f1d2453ceb08c9bcc4939766, 4.4.133 ≤ v < 4.5, 4.9.103 ≤ v < 4.10, 4.14.44 ≤ v < 4.15, 4.16.12 ≤ v < 4.17, 4.17 | bcd4df60ac9481b1ceffdfe5ec38fe51dcaae812, 78a47127e33c340bc6d38dcc4552a094b4f5cc77, 142e287b3a25cfe909215177c23243e7fc5ae2b1, 91f041451f967cd87ed722a8f43c0b767a64f1a0, 9052756290962ffb9a661bcf319e92dedaaedfed, 5bb10753d428aadfc356a2bfe9acea09c82a62ec, b06b6fce6d7deaf7238e09b48ce3b1125ff41acd, 03390aa32e669cc4ecd7d34108e2e1afc13d689d, 4.5, 4.10, 4.15, 4.17 |
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