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High 7.1Published Jun 25, 2026

CVE-2026-53223net: guard timestamp cmsgs to real error queue skbs

Updated under an hour ago ()

Does this affect you?

It affects Linux and 4 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Weakness (CWE)
Not given
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
Linux
NVD analysis
Modified
Record last updated
Oct 16, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Linux Linux
linux:linux (from the name)
8605330aac5a5785630aec8f64378a54891937cc builds before 24a0d548d3a765cd4558224e4f8e06e14cba26e3; 8605330aac5a5785630aec8f64378a54891937cc builds before 71ff5cdd5da61d0438e902aa0fd68c28bc901abe; from 8605330aac5a5785630aec8f64378a54891937cc before ad9a0374ee6d11048e1f74cd5180bad58b9848b4; from 8605330aac5a5785630aec8f64378a54891937cc before b903e9b5629ec8dd6db92174070045bf81ad7060; from 8605330aac5a5785630aec8f64378a54891937cc before e0665b2a8e90bb08bd205062c75662b502d31797; 8605330aac5a5785630aec8f64378a54891937cc builds before 3dde4fb941fa5649ab809f6cd3e20e0c424a4e31; from 8605330aac5a5785630aec8f64378a54891937cc before eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a; 8605330aac5a5785630aec8f64378a54891937cc builds before 1ee90b77b727df903033db873c75caac5c27ec98; and 2 more ranges
CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)
from V3.1.6
CISA ADP
linux linux_kernel
linux:linux_kernel
from 4.10.14 before 4.11; from 4.11.1 before 5.10.259; from 5.11 before 5.15.210; from 5.16 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13; and 13 more ranges
NVD

References

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The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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