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

Status: published. Published: 2026-06-25. Updated: 2026-11-10.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 8605330aac5a5785630aec8f64378a54891937cc; < 24a0d548d3a765cd4558224e4f8e06e14cba26e3 (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < 71ff5cdd5da61d0438e902aa0fd68c28bc901abe (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < ad9a0374ee6d11048e1f74cd5180bad58b9848b4 (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < b903e9b5629ec8dd6db92174070045bf81ad7060 (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < e0665b2a8e90bb08bd205062c75662b502d31797 (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < 3dde4fb941fa5649ab809f6cd3e20e0c424a4e31 (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a (affected, git); ≥ 8605330aac5a5785630aec8f64378a54891937cc; < 1ee90b77b727df903033db873c75caac5c27ec98 (affected, git); cdaf15b43bd31003220cb080bcbbd57787a2fca9 (affected, git); ≥ 4.10.14; < 4.11 (affected, semver). Source: CNA: Linux
- Linux / Linux: 4.11 (affected); ≥ 0; < 4.11 (unaffected, semver); ≥ 5.10.259; ≤ 5.10.* (unaffected, semver); ≥ 5.15.210; ≤ 5.15.* (unaffected, semver); ≥ 6.1.176; ≤ 6.1.* (unaffected, semver); ≥ 6.6.143; ≤ 6.6.* (unaffected, semver); ≥ 6.12.94; ≤ 6.12.* (unaffected, semver); ≥ 6.18.36; ≤ 6.18.* (unaffected, semver); ≥ 7.0.13; ≤ 7.0.* (unaffected, semver); ≥ 7.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 7.1 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H; source: CNA: Linux

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-09; percentile 3.08%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/24a0d548d3a765cd4558224e4f8e06e14cba26e3 (CNA: Linux)

- https://git.kernel.org/stable/c/71ff5cdd5da61d0438e902aa0fd68c28bc901abe (CNA: Linux)

- https://git.kernel.org/stable/c/ad9a0374ee6d11048e1f74cd5180bad58b9848b4 (CNA: Linux)

- https://git.kernel.org/stable/c/b903e9b5629ec8dd6db92174070045bf81ad7060 (CNA: Linux)

- https://git.kernel.org/stable/c/e0665b2a8e90bb08bd205062c75662b502d31797 (CNA: Linux)

- https://git.kernel.org/stable/c/3dde4fb941fa5649ab809f6cd3e20e0c424a4e31 (CNA: Linux)

- https://git.kernel.org/stable/c/eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a (CNA: Linux)

- https://git.kernel.org/stable/c/1ee90b77b727df903033db873c75caac5c27ec98 (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-53223; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-53223; retrieved 2026-11-10; source updated Not reported

Revision: 04a0f35519db656abd12fd014686eb3d8cfc4626addda605a1467282f2928de0

Canonical: https://y2.dev/cve/CVE-2026-53223

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