CVE-2026-52937 PUBLISHED

tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

Assigner: Linux
Reserved: 09.06.2026 Published: 24.06.2026 Updated: 24.06.2026

In the Linux kernel, the following vulnerability has been resolved:

tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an uninitialised on-stack struct sockaddr_storage to userspace via ifr_hwaddr, but netif_get_mac_address() only writes sa_family and dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised.

Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a macvtap chardev returns kernel .text and direct-map pointers, defeating KASLR.

Initialise ss at declaration.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 3b23a32a63219f51a5298bc55a65ecee866e79d0 to 719007c3492f0f1f9e9cdbed8ac45ba45bb13eeb (excl.)
  • affected from 3b23a32a63219f51a5298bc55a65ecee866e79d0 to 05305e832be7b9d65b2b72caacf7d850b3942b2a (excl.)
  • affected from 3b23a32a63219f51a5298bc55a65ecee866e79d0 to bddc09212c24934643bd44fc794748d2bbb3b6cd (excl.)
  • Version 176188cff67ec1aa55103647b61d02315cc38e98 is affected
  • Version 1fc205d9e400f069ebf30d3faa6ec2bab2cbd7b4 is affected
  • Version 4d0ae760c02c98fc78b78d3a0509896bc648ad1c is affected
  • affected from 5.4.103 to 5.5 (excl.)
  • affected from 5.10.21 to 5.11 (excl.)
  • affected from 5.11.4 to 5.12 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 5.12 is affected
  • unaffected from 0 to 5.12 (excl.)
  • unaffected from 6.18.34 to 6.18.* (incl.)
  • unaffected from 7.0.11 to 7.0.* (incl.)
  • unaffected from 7.1 to * (incl.)

References