CVE-2026-53223

Description

In the Linux kernel, the following vulnerability has been resolved: net: guard timestamp cmsgs to real error queue skbs skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb from sk_error_queue. That assumption is not true for AF_PACKET sockets: outgoing packet taps are also delivered to packet sockets with skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET instead of struct sock_exterr_skb. If such an skb is received with timestamping enabled, the generic timestamp cmsg path can read AF_PACKET control-buffer state as sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop counter overlaps opt_stats. An odd drop count makes the path emit SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear skbs this copies past the linear head and can trigger hardened usercopy or disclose adjacent heap contents. Keep skb_is_err_queue() local to net/socket.c, but make it verify that the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal receive ownership and no longer pass as error-queue skbs, while legitimate sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free ownership.

CVSS breakdown

Affected products

• Linux / Linux6.18.36 – 6.18.*
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – 24a0d548d3a765cd4558224e4f8e06e14cba26e3
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – 71ff5cdd5da61d0438e902aa0fd68c28bc901abe
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – ad9a0374ee6d11048e1f74cd5180bad58b9848b4
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – b903e9b5629ec8dd6db92174070045bf81ad7060
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – e0665b2a8e90bb08bd205062c75662b502d31797
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – 3dde4fb941fa5649ab809f6cd3e20e0c424a4e31
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a
• Linux / Linux8605330aac5a5785630aec8f64378a54891937cc – 1ee90b77b727df903033db873c75caac5c27ec98
• Linux / Linuxcdaf15b43bd31003220cb080bcbbd57787a2fca9 – cdaf15b43bd31003220cb080bcbbd57787a2fca9
• Linux / Linux4.10.14 – 4.11
• Linux / Linux4.11 – 4.11
• Linux / Linux0 – 4.11
• Linux / Linux5.10.259 – 5.10.*
• Linux / Linux5.15.210 – 5.15.*
• Linux / Linux6.1.176 – 6.1.*
• Linux / Linux6.6.143 – 6.6.*
• Linux / Linux6.12.94 – 6.12.*
• Linux / Linux7.0.13 – 7.0.*
• Linux / Linux7.1 – *

References

• MISChttps://git.kernel.org/stable/c/24a0d548d3a765cd4558224e4f8e06e14cba26e3
• MISChttps://git.kernel.org/stable/c/71ff5cdd5da61d0438e902aa0fd68c28bc901abe
• MISChttps://git.kernel.org/stable/c/ad9a0374ee6d11048e1f74cd5180bad58b9848b4
• MISChttps://git.kernel.org/stable/c/b903e9b5629ec8dd6db92174070045bf81ad7060
• MISChttps://git.kernel.org/stable/c/e0665b2a8e90bb08bd205062c75662b502d31797
• MISChttps://git.kernel.org/stable/c/3dde4fb941fa5649ab809f6cd3e20e0c424a4e31
• MISChttps://git.kernel.org/stable/c/eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a
• MISChttps://git.kernel.org/stable/c/1ee90b77b727df903033db873c75caac5c27ec98